{"id":23923,"date":"2022-04-05T15:31:01","date_gmt":"2022-04-05T10:01:01","guid":{"rendered":"https:\/\/ccssmathanswers.com\/?p=23923"},"modified":"2022-04-07T11:30:06","modified_gmt":"2022-04-07T06:00:06","slug":"big-ideas-math-answers-grade-1-chapter-4","status":"publish","type":"post","link":"https:\/\/bigideasmathanswers.com\/big-ideas-math-answers-grade-1-chapter-4\/","title":{"rendered":"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20"},"content":{"rendered":"<p>In Order to attempt the 1st Grade Exam, you need to have strong fundamentals. Download Big Ideas Math Book 1st Grade Answer Key Chapter 4 Add Numbers within 20 free of cost and get the homework help you need. Attempt the practice test to know your preparation level within the Chapter. Practice as much as you can using the <a href=\"https:\/\/bigideasmathanswers.com\/big-ideas-math-answers-grade-1\/\">Big Ideas Math Answers Grade 1<\/a> Chapter 4 Add Numbers within 20 and clear the exam with better scores.<\/p>\n<h2>Big Ideas Math Book 1st Grade Answer Key Chapter 4 Add Numbers within 20<\/h2>\n<p>You can make the most out of the Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 through the quick links available. Simply tap on the topic you want and solve various questions involved in it easily. There are various models in addition and subtraction. We have listed all of them by considering enough examples and explained every problem step by step.<\/p>\n<p><strong>Vocabulary<\/strong><\/p>\n<ul>\n<li><a href=\"#Add_Numbers_within_20_Vocabulary\">Add Numbers within 20 Vocabulary<\/a><\/li>\n<\/ul>\n<p><strong>Lesson: 1 Add Doubles from 6 to 10<\/strong><\/p>\n<ul>\n<li><a href=\"#Lesson_4.1_Add_Doubles_from_6_to_10\">Lesson 4.1 Add Doubles from 6 to 10<\/a><\/li>\n<li><a href=\"#Add_Doubles_from_6_to_10_Practice_4.1\">Add Doubles from 6 to 10 Practice 4.1<\/a><\/li>\n<\/ul>\n<p><strong>Lesson: 2 Use Doubles within 20<\/strong><\/p>\n<ul>\n<li><a href=\"#Lesson_4.2_Use_Doubles_within_20\">Lesson 4.2 Use Doubles within 20<\/a><\/li>\n<li><a href=\"#Use_Doubles_within_20_Practice_4.2\">Use Doubles within 20 Practice 4.2<\/a><\/li>\n<\/ul>\n<p><strong>Lesson: 3 Count on to Add within 20<\/strong><\/p>\n<ul>\n<li><a href=\"#Lesson_4.3_Count_on_to_Add_within_20\">Lesson 4.3 Count on to Add within 20<\/a><\/li>\n<li><a href=\"#Count_on_to_Add_within_20_Practice_4.3\">Count on to Add within 20 Practice 4.3<\/a><\/li>\n<\/ul>\n<p><strong>Lesson 4: Add Three Numbers<\/strong><\/p>\n<ul>\n<li><a href=\"#Lesson_4.4_Add_Three_Numbers\">Lesson 4.4 Add Three Numbers<\/a><\/li>\n<li><a href=\"#Add_Three_Numbers_Practice_4.4\">Add Three Numbers Practice 4.4<\/a><\/li>\n<\/ul>\n<p><strong>Lesson 5 Add Three Numbers by Making a 10<\/strong><\/p>\n<ul>\n<li><a href=\"#Lesson_4.5_Add_Three_Numbers_by_Making_a_10\">Lesson 4.5 Add Three Numbers by Making a 10<\/a><\/li>\n<li><a href=\"#Add_Three_Numbers_by_Making_a_10_Practice_4.5\">Add Three Numbers by Making a 10 Practice 4.5<\/a><\/li>\n<\/ul>\n<p><strong>Lesson: 6 Add 9<\/strong><\/p>\n<ul>\n<li><a href=\"#Lesson_4.6_Add_9\">Lesson 4.6 Add 9<\/a><\/li>\n<li><a href=\"#Add_9_Practice_4.6\">Add 9 Practice 4.6<\/a><\/li>\n<\/ul>\n<p><strong>Lesson 7 Make a 10 to Add<\/strong><\/p>\n<ul>\n<li><a href=\"#Lesson_4.7_Make_a_10_ Add\">Lesson 4.7 Make a 10 to Add<\/a><\/li>\n<li><a href=\"#Make_a_10_ Add_Practice_4.7\">Make a 10 to Add Practice 4.7<\/a><\/li>\n<\/ul>\n<p><strong>Lesson: 8 Problem Solving: Addition within 20<\/strong><\/p>\n<ul>\n<li><a href=\"_Addition_within_20\">Lesson 4.8 Problem Solving: Addition within 20<\/a><\/li>\n<li><a href=\"_Addition_within_20_Practice_4.8\">Problem Solving: Addition within 20 Practice 4.8<\/a><\/li>\n<\/ul>\n<p><strong>Performance Task<\/strong><\/p>\n<ul>\n<li><a href=\"#Add_Numbers_within_20_Performance_Task\">Add Numbers within 20 Performance Task<\/a><\/li>\n<li><a href=\"#Add_Numbers_within_20_Chapter_Practice\">Add Numbers within 20 Chapter Practice<\/a><\/li>\n<li><a href=\"#Use_Doubles_within_20_Homework_&amp;_Practice_4.2\">Use Doubles within 20 Homework &amp; Practice 4.2<\/a><\/li>\n<li><a href=\"#count_on_to_within_20_Homework_&amp;_Practice_4.3\">Count on to Add within 20 Homework &amp; Practice 4.3<\/a><\/li>\n<li><a href=\"#Add_Three_Numbers_Homework_&amp;_Practice_4.4\">Add Three Numbers Homework &amp; Practice 4.4<\/a><\/li>\n<li><a href=\"#Add_Three_Numbers_by_making_a_10_Homework_&amp;_Practice_4.5\">Add Three Numbers by Making a 10 Homework &amp; Practice 4.5<\/a><\/li>\n<li><a href=\"#Add_9_Homework_&amp;_Practice_4.6\">Add 9 Homework &amp; Practice 4.6<\/a><\/li>\n<li><a href=\"#making_a_10_to_add_homework_&amp;_Practice_4.7\">Make a 10 to Add Homework &amp; Practice 4.7<\/a><\/li>\n<li><a href=\"_Addition_within_20_homework_&amp;_Practice_4.8\">Problem Solving: Addition within 20 Homework &amp; Practice 4.8<\/a><\/li>\n<\/ul>\n<h3><a id=\"Add_Numbers_within_20_Vocabulary\"><\/a>Add Numbers within 20 Vocabulary<\/h3>\n<p><strong>Organize It<\/strong><\/p>\n<p>Review Words:<br \/>\naddend<br \/>\ndoubles<br \/>\ndoubles minus 1<br \/>\ndoubles plus 1<br \/>\nsum<\/p>\n<p>Use the review words to complete the graphic organizer.<\/p>\n<p><img loading=\"lazy\" class=\"alignnone size-full wp-image-24035\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-1.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 1\" width=\"384\" height=\"281\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-1.png 384w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-1-300x220.png 300w\" sizes=\"(max-width: 384px) 100vw, 384px\" \/><\/p>\n<p>Answer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-26888 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-within-20.bmp\" alt=\"\" width=\"384\" height=\"290\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-within-20.bmp 384w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-within-20-300x227.jpg 300w\" sizes=\"(max-width: 384px) 100vw, 384px\" \/><\/p>\n<p>Explanation:<br \/>\nBy Looking at graphic organizer<br \/>\n1.\u00a0 Here we have 2 blocks and in second block we have one more added,<br \/>\nso we write the review words as doubles plus 1.<br \/>\n2. Here we have only two block so we write the review words as doubles.<br \/>\n3. Here also we have 2 blocks, but in second block on one dot it is crossed,<br \/>\nso we write the review words as doubles minus 1.<\/p>\n<p><strong>Define It<\/strong><\/p>\n<p>Match the review word to its definition.<\/p>\n<p><img loading=\"lazy\" class=\"alignnone size-full wp-image-24034\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-2.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 2\" width=\"380\" height=\"104\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-2.png 380w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-2-300x82.png 300w\" sizes=\"(max-width: 380px) 100vw, 380px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-26908 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-1.bmp\" alt=\"\" width=\"405\" height=\"328\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-1.bmp 405w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-1-300x243.jpg 300w\" sizes=\"(max-width: 405px) 100vw, 405px\" \/><\/p>\n<p>Explanation:<br \/>\nAddend means any of the numbers that are added together.<br \/>\nSum can be defined as the result or answer we get on adding two or more numbers or terms.<br \/>\nHere 1. 5 + 3 = 8\u00a0 numbers 5, 3 are addends and 8 is sum<br \/>\n2. 4 + 3 = 7 number 4,3 are addends and 7 is sum.<\/p>\n<h3><a id=\"Lesson_4.1_Add_Doubles_from_6_to_10\"><\/a>Lesson 4.1 Add Doubles from 6 to 10<\/h3>\n<p><strong>Explore and Grow<\/strong><\/p>\n<p>Use counters to model the story.<\/p>\n<p>You have 7 marbles. Your friend has 7 marbles. How many marbles are there in all?<\/p>\n<p><img loading=\"lazy\" class=\"alignnone size-full wp-image-24069\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-3.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 3\" width=\"441\" height=\"405\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-3.png 441w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-3-300x276.png 300w\" sizes=\"(max-width: 441px) 100vw, 441px\" \/><br \/>\nAnswer:<br \/>\nIn all, there are total of 14 marbles.<\/p>\n<p>Explanation:<br \/>\nGiven I have 7 marbles and my friend has 7 marbles,<br \/>\nThe total number of marbles available are ( my marbles and friend&#8217;s marble),<br \/>\n7 + 7 = 14 marbles. So 14 marbles are there in all.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 1.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24068\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-4.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 4\" width=\"157\" height=\"56\" \/><br \/>\n___8____ + ___8___ = __16_____<br \/>\nAnswer:<br \/>\n8 + 8 = 16 dots<\/p>\n<p>Explanation:<br \/>\nGiven in block 1 we have 8 dots and in block 2 we have 8 dots,<br \/>\nSo in total we have 8 + 8 = 16 dots.<\/p>\n<p>Question 2.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24067\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-5.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 5\" width=\"135\" height=\"60\" \/><br \/>\n____7___ + __7____ = ___14____<br \/>\nAnswer:<br \/>\n7 + 7 = 14 dots<\/p>\n<p>Explanation:<br \/>\nGiven in block 1 we have 7 dots and in block 2 we have 7 dots,<br \/>\nSo in total we have 7 + 7 = 14 dots.<\/p>\n<p>Question 3.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24066\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-6.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 6\" width=\"190\" height=\"169\" \/> =<br \/>\nAnswer:<br \/>\n9 + 9 = 18 dots<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-27750 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-11.bmp\" alt=\"\" width=\"219\" height=\"173\" \/><br \/>\nExplanation:<br \/>\nGiven in block 1 we have 9 dots and in block 2 we have 9 dots,<br \/>\nSo in total we have 9 + 9 = 18 dots.<\/p>\n<p>Question 4.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24065\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-7.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 7\" width=\"190\" height=\"186\" \/><\/p>\n<p>Answer:<br \/>\n10 + 10 = 20 dots<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-27751 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-12.bmp\" alt=\"\" width=\"230\" height=\"188\" \/><br \/>\nExplanation:<br \/>\nGiven in block 1 we have 10 dots and in block 2 we have 10 dots,<br \/>\nSo in total we have 10 + 10 = 20 dots.<\/p>\n<p>Question 5.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24064\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-8.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 8\" width=\"153\" height=\"61\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-8.png 153w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-8-150x61.png 150w\" sizes=\"(max-width: 153px) 100vw, 153px\" \/><br \/>\n____8___ + _8_____ = _______<br \/>\nAnswer:<br \/>\n8 + 8 = 16 dots<\/p>\n<p>Explanation:<br \/>\nGiven in block 1 we have 8 dots and in block 2 we have 8 dots,<br \/>\nSo in total we have 8 + 8 = 16 dots.<\/p>\n<p>Question 6.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24063\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-9.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 9\" width=\"121\" height=\"56\" \/><br \/>\n___6____ + __6___ = ___12____<br \/>\nAnswer:<br \/>\n6 + 6 = 12 dots<\/p>\n<p>Explanation:<br \/>\nGiven in block 1 we have 6 dots and in block 2 we have 6 dots,<br \/>\nSo in total we have 6 + 6 = 12 dots.<\/p>\n<p>Question 7.<br \/>\n7 + 7 = ___14____<br \/>\nAnswer:<br \/>\n7 + 7 = 14 dots<\/p>\n<p>Explanation:<br \/>\nGiven first number is 7 and second number is 7,<br \/>\nSo in total we have 7 + 7 = 14 dots.<\/p>\n<p>Question 8.<br \/>\n10 + 10 = ___20_____<br \/>\nAnswer:<br \/>\n10 + 10 = 20<\/p>\n<p>Explanation:<br \/>\nGiven first number is 10 and second number is 10,<br \/>\nSo in total we have 10 + 10 = 20.<\/p>\n<p>Question 9.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24062\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-10.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 10\" width=\"69\" height=\"104\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-27754 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-7-1.bmp\" alt=\"\" width=\"90\" height=\"111\" \/><\/p>\n<p>Explanation:<br \/>\nGiven first number as 9 and second number as 9,<br \/>\nSo in total we have 9 + 9 = 18.<\/p>\n<p>Question 10.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24061\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-11.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 11\" width=\"64\" height=\"104\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-27755 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-8.bmp\" alt=\"\" width=\"90\" height=\"111\" \/><\/p>\n<p>Explanation:<br \/>\nGiven first number as 8 and second number as 8,<br \/>\nSo in total we have 8 + 8 = 16.<\/p>\n<p>Question 11.<br \/>\n<strong>MP Reasoning<\/strong><br \/>\nYou and your friend each read 6 books. How many books do you and your friend read in all?<br \/>\n____12______ books<br \/>\nAnswer:<br \/>\nTotal number of books I and my friend read are 12.<\/p>\n<p>Explanation:<br \/>\nGiven I and my friend each read 6 books, that means I read 6 books,<br \/>\nmy friend read 6 books, So in total we read 6 + 6 = 12.<\/p>\n<p><strong>Think and Grow: Modeling Real Life<\/strong><\/p>\n<p>You and your friend have the same number of video games. There are 16 in all. How many video games do you have?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24060\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-12.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 12\" width=\"122\" height=\"111\" \/><br \/>\nDraw a Picture:<\/p>\n<p>Addition equation: X + X = 16,<\/p>\n<p>___8_______ video games<br \/>\nAnswer:<br \/>\nI have 8 number of video games.<\/p>\n<p>Explanation:<br \/>\nGiven I and my friend have same number of video games,<br \/>\nSo in all both have 16 video games , Let us take I have X number of video games,<br \/>\nmeans friend will also have X number of video games,<br \/>\nNow addition equation is X + X = 16, 2 X = 16 , So X = 16 \u00f7 2 = 8,<br \/>\nSo I have 8 video games.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 12.<br \/>\n2 friends give you the same number of pictures. You have 12 in all. How many pictures does each friend give you?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24059\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-13.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 13\" width=\"137\" height=\"219\" \/><br \/>\nDraw a Picture:<\/p>\n<p>Addition equation:<br \/>\nX + X = 12,<\/p>\n<p>____6______ pictures<br \/>\nAnswer:<br \/>\nEach friend gives 6 pictures to me.<\/p>\n<p>Explanation:<br \/>\nGiven 2 friends gave me same number of pictures,<br \/>\nSo in all both gave 12 pictures , Let us take each gave X number of pictures,<br \/>\nSo we write addition equation as X + X = 12, 2 X = 12 , So X = 12 \u00f7 2 = 6,<br \/>\nSo each friend gave me 6 number of pictures.<\/p>\n<h3><a id=\"Add_Doubles_from_6_to_10_Practice_4.1\"><\/a>Add Doubles from 6 to 10 Practice 4.1<\/h3>\n<p>Question 1.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24058\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-14.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 14\" width=\"240\" height=\"71\" \/><br \/>\n____10______ + ____10______ = ___20______<br \/>\nAnswer:<br \/>\n10 + 10 = 20 dots<\/p>\n<p>Explanation:<br \/>\nGiven in block 1 we have 10 dots and in block 2 we have 10 dots,<br \/>\nSo in total we have 10 + 10 = 20 dots.<\/p>\n<p>Question 2.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24057\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-15.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 15\" width=\"147\" height=\"71\" \/><br \/>\n_____6_____ + ____6______ = ____12_____<br \/>\nAnswer:<br \/>\n6 + 6 = 12 dots<\/p>\n<p>Explanation:<br \/>\nGiven in block 1 we have 6 dots and in block 2 we have 6 dots,<br \/>\nSo in total we have 6 + 6 = 12 dots.<\/p>\n<p>Question 3.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24056\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-16.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 16\" width=\"84\" height=\"128\" \/><br \/>\nAnswer:<\/p>\n<p><img loading=\"lazy\" class=\"alignnone wp-image-27756 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-7-2.bmp\" alt=\"\" width=\"90\" height=\"111\" \/><br \/>\nExplanation:<br \/>\nGiven first number as 9 and second number as 9,<br \/>\nSo in total we have 9 + 9 = 18.<\/p>\n<p>Question 4.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24055\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-17.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 17\" width=\"81\" height=\"127\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-27757 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-9.bmp\" alt=\"\" width=\"90\" height=\"127\" \/><\/p>\n<p>Explanation:<br \/>\nGiven first number as 10 and second number as 10,<br \/>\nSo in total we have 10 + 10 = 20.<\/p>\n<p>Question 5.<br \/>\n<strong>MP Reasoning<\/strong><br \/>\nYou and your friend each do 7 jumping jacks. How many jumping jacks do you and your friend do in all?<\/p>\n<p>____14______ jumping jacks<br \/>\nAnswer:<br \/>\n14 jumping jacks I and my friend do in all .<\/p>\n<p>Explanation:<br \/>\nGiven I and my friend each do 7 jumping jacks,<br \/>\nmeans I did 7 jumping jacks, My friend did 7 jumping jacks,<br \/>\nSo both overall did 7 + 7 = 14 jumping jacks.<\/p>\n<p>Question 6.<br \/>\n<strong>Modeling Real Life<\/strong><br \/>\nNewton and Descartes each have the same number of treats. They have 18 treats in all.<br \/>\nHow many treats does Newton have?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24054\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-18.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 18\" width=\"140\" height=\"88\" \/><\/p>\n<p>____9______ treats<br \/>\nAnswer:<br \/>\nNewton have 9 treats.<\/p>\n<p>Explanation:<br \/>\nGiven Newton and Descartes each have the same number of treats,<br \/>\nSuppose if\u00a0 Newton have\u00a0 X treats means Descartes have same X treats<br \/>\nand in all both have 18 treats, So X + X = 18 , 2X = 18 , X = 18 \u00f7 2 = 9,<br \/>\nSo Newton has 9 treats.<\/p>\n<p><strong>Review &amp; Refresh<\/strong><\/p>\n<p>Use the picture to write an equation.<\/p>\n<p>Question 7.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24053\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-19.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 19\" width=\"252\" height=\"126\" \/><br \/>\n____3______ + ____2_____ = ____5_____<br \/>\nAnswer:<br \/>\n3 + 2 = 5<\/p>\n<p>Explanation:<br \/>\nBy seeing the picture there are 3 children sitting and reading books on the chair and<br \/>\n2 children are having bags and going to school, So we write the equation as<br \/>\n3 + 2 = 5.<\/p>\n<p>Question 8.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24052\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-20.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 20\" width=\"251\" height=\"125\" \/><br \/>\n___5_______ + ____1_____ = ____6_____<br \/>\nAnswer:<br \/>\n5 + 1 = 6<\/p>\n<p>Explanation:<br \/>\nBy seeing the picture there are 5 children sitting on the ground and reading books,<br \/>\n1 child having book is waving hand, So we write the equation as<br \/>\n5 + 1 = 6.<\/p>\n<h3><a id=\"Lesson_4.2_Use_Doubles_within_20\"><\/a>Lesson 4.2 Use Doubles within 20<\/h3>\n<p><strong>Explore and Grow<\/strong><\/p>\n<p>Use counters to model the story.<\/p>\n<p>You collect 8 leaves. Your friend collects 8 leaves. How many leaves are there in all?<\/p>\n<p>____16_____ leaves<br \/>\nExplanation:<br \/>\nBoth I and friend collect same leaves ,<br \/>\n8 + 8 = 16 leaves we call the sum as doubles as both addends are 8.<\/p>\n<p>You collect 1 more leaf. How many leaves are there now?<\/p>\n<p>_____17_____ leaves<br \/>\nExplanation:<br \/>\nWe got doubles as 16, Now the required sum is one more than doubles,<br \/>\nThat is 17,Therefore 8+8+1= 17 so we call as double plus 1.<\/p>\n<p><img loading=\"lazy\" class=\"alignnone size-full wp-image-24084\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-21.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 21\" width=\"429\" height=\"205\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-21.png 429w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-21-300x143.png 300w\" sizes=\"(max-width: 429px) 100vw, 429px\" \/><\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 1.<br \/>\nUse the double 6 + 6 to find each sum.<br \/>\n6 + 7 = ___13____<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24083\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-22.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 22\" width=\"149\" height=\"70\" \/><br \/>\nAnswer:<br \/>\n6 + 7= 13<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-26978 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-2.bmp\" alt=\"\" width=\"315\" height=\"110\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-2.bmp 315w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-2-300x105.jpg 300w\" sizes=\"(max-width: 315px) 100vw, 315px\" \/><\/p>\n<p>Explanation:<br \/>\nWe Know the double\u00a0 6 + 6 = 12 , The number 7 is one more than 6,<br \/>\nSo we can write 7 as 6 + 1, The required sum is one more than double,<br \/>\n12 + 1 =13, Sum is 13, therefore 6 + 7 = 13, Double plus 1.<\/p>\n<p>6 + 5 = ___11____<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24082\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-23.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 23\" width=\"146\" height=\"68\" \/><br \/>\nAnswer:<br \/>\n6+5 = 11<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-26984 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-3.bmp\" alt=\"\" width=\"315\" height=\"110\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-3.bmp 315w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-3-300x105.jpg 300w\" sizes=\"(max-width: 315px) 100vw, 315px\" \/><\/p>\n<p>Explanation:<br \/>\nWe Know the double of 6 + 6 = 12 , The number 5 is one less than 6,<br \/>\nSo we can write 5 as 6 &#8211; 1, The required sum is one less than double,<br \/>\n12 &#8211; 1 = 11, Sum is 11, therefore 6 + 5 = 11, Double minus 1.<\/p>\n<p><strong>Apply and Grow: Practice<\/strong><\/p>\n<p>Use the double 7 + 7 to find each sum.<\/p>\n<p>Question 2.<br \/>\n7 + 8 = ___15_____<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24081\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-24.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 24\" width=\"170\" height=\"68\" \/><br \/>\nAnswer:<br \/>\n7 + 8 = 15<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-27447 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-4.bmp\" alt=\"\" width=\"441\" height=\"119\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-4.bmp 441w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-4-300x81.jpg 300w\" sizes=\"(max-width: 441px) 100vw, 441px\" \/><\/p>\n<p>Explanation:<br \/>\nWe know the double of 7 + 7 = 14 , The number 8 is one more than 7,<br \/>\nSo we can write 8 as 7 + 1, The required sum is one more than double,<br \/>\n14 + 1 =15, Sum is 15, therefore 7 + 8 = 15, Double plus 1.<\/p>\n<p>7 + 6 = ____13_____<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24080\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-25.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 25\" width=\"166\" height=\"68\" \/><br \/>\nAnswer:<br \/>\n7 + 6 = 13<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-27521 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-5.bmp\" alt=\"\" width=\"370\" height=\"116\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-5.bmp 370w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-5-300x94.jpg 300w\" sizes=\"(max-width: 370px) 100vw, 370px\" \/><\/p>\n<p>Explanation:<br \/>\nWe know the double of 7+ 7 = 14 , The number 6 is one less than 7,<br \/>\nSo we can write 6 as 7 &#8211; 1, The required sum is one less than double,<br \/>\n14 &#8211; 1 = 13, Sum is 13, therefore 7 + 6 = 13, Double minus 1.<\/p>\n<p>Find the sum. Write the double you used.<\/p>\n<p>Question 3.<br \/>\n5 + 6 = ___11______<\/p>\n<p>___5_+5__+_ \u25cb ___1___ = ___11____<br \/>\nAnswer:<br \/>\n5 + 6 = 11, we use double 5 + 5,<\/p>\n<p>Explanation:<br \/>\nAs the first addend is 5 and we know the double is 5 + 5 ,<br \/>\nSo 5 + 5 = 10 , The number 6 is one more than 5,<br \/>\nSo we can write 6 as 5 + 1, The required sum is one more than double,<br \/>\n10 + 1 =11, Sum is 11, therefore 5 + 6 = 11, Double plus 1.<br \/>\nWe use double 5 + 5.<\/p>\n<p>Question 4.<br \/>\n9 + 8 = ___17______<\/p>\n<p>___9+9 -____ \u25cb ___1____ = __17_____<br \/>\nAnswer:<br \/>\n9 + 8 = 17, we use double 9 + 9 ,<\/p>\n<p>Explanation:<br \/>\nAs the first addend is 9 and we know the double is 9 + 9,<br \/>\n9 + 9 = 18 , The number 8 is one less than 9,<br \/>\nSo we can write 8 as 9 &#8211; 1, The required sum is one less than double,<br \/>\n18 &#8211; 1 = 17, Sum is 17, therefore 9 + 8 = 17, Double minus 1.<br \/>\nWe use double 9 + 9<\/p>\n<p>Question 5.<br \/>\n<strong>DIG DEEPER!<\/strong><br \/>\nCircle two ways you can solve 9 + 10. Show how you know.<br \/>\n9 + 9 and 1 more<br \/>\n9 + 9 and 1 less<br \/>\n10 &#8211; 10 and 1 more<br \/>\n10 + 10 and 1 less<br \/>\nAnswer:<br \/>\nTo solve 9 + 10 the two ways\u00a0 which we can solve are<br \/>\n9 + 9 and 1 more and other is 10 + 10 and 1 less.<br \/>\n<a href=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-6.bmp\"><img loading=\"lazy\" class=\"alignnone size-full wp-image-27732\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-6.bmp\" alt=\"\" width=\"208\" height=\"152\" \/><\/a><br \/>\nExplanation:<br \/>\nWe know 9 + 10 = 19 now we will see which way we can solve,<br \/>\n1. 9 + 9 and 1 more means , it is 18 + 1 which is equal to 19,<br \/>\nSimilar to 9 + 10 = 19 , therefore we can solve with 9 + 9 and 1 more .<br \/>\n2. 9 + 9 and 1 less means it is 18 &#8211; 1 which is 17,<br \/>\nAs 17 is not equal to 9 + 10 = 19, So 9 + 9 and 1 less way we will not solve 9 + 10 .<br \/>\n3. 10 &#8211; 10 and 1 more means 0 + 1 = 1 , here this is not equal to 9 + 10,<br \/>\nSo by 10 &#8211; 10 and 1 more way we will not solve for 9 + 10.<br \/>\n4. 10 + 10 and 1 less means 10 + 9 = 19 which is equal to 9 + 10 ,<br \/>\nSo 10 + 10 and 1 less way we will solve 9 + 10.<br \/>\nTherefore to solve 9 + 10 the two ways which we can solve are<br \/>\n9 + 9 and 1 more and other is 10 + 10 and 1 less.<\/p>\n<p><strong>Think and Grow: Modeling Real Life<\/strong><\/p>\n<p>A music room has 7 keyboards. There is 1 more recorder than keyboards. How many instruments are there?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24079\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-26.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 26\" width=\"193\" height=\"83\" \/><br \/>\nWhich doubles can you use to find the sum?<br \/>\n7 + 7\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 8 + 8\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 6 + 6<br \/>\nEquation:<\/p>\n<p>__15_____ instruments<br \/>\nAnswer:<br \/>\nThere are 15 instruments in the music room.<br \/>\nWe use doubles 7 + 7\u00a0 to find the sum 7 + 8 = 15.<\/p>\n<p>Explanation:<br \/>\nGiven a music room has 7 keyboards and there are\u00a0 1 more recorder than keyboards,<br \/>\nmeans number of recorders are 7 + 1 = 8, so total number of instruments in room are<br \/>\n7+ 8 = 7 + 7 + 1 = 15, Here we have used doubles 7 + 7.<br \/>\nTherefore\u00a0 to find the sum we use doubles 7 + 7 and the sum is 7 + 8 = 15.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 6.<br \/>\nA museum has lo paintings. There is 1 fewer sculpture than paintings. How many art pieces are there?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24078\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-27.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 27\" width=\"168\" height=\"93\" \/><br \/>\nWhich doubles can you use to find the sum?<br \/>\n8 + 8\u00a0 \u00a0 \u00a0 \u00a0 9 + 9\u00a0 \u00a0 \u00a0 10 + 10<br \/>\nEquation:<\/p>\n<p>____19______ art pieces<br \/>\nAnswer:<br \/>\nThere are 19 art pieces, We use doubles 10 + 10\u00a0 to find the sum 10 + 9 = 19.<\/p>\n<p>Explanation:<br \/>\nGiven a museum has 10 paintings and there is 1 fewer sculpture than paintings,<br \/>\nmeans number of sculptures are one less than paintings 10 &#8211; 1 = 9,<br \/>\nSo total number of art pieces are 10 + 9 = 10 + 10 &#8211; 1 = 19,<br \/>\nHere we have used doubles 10 + 10.<br \/>\nTherefore\u00a0 to find the sum we use doubles 10 + 10 and the sum is 10 + 9 = 19.<\/p>\n<h3><a id=\"Use_Doubles_within_20_Practice_4.2\"><\/a>Use Doubles within 20 Practice 4.2<\/h3>\n<p>Question 1.<br \/>\n9 + 10 = ____19____<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24077\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-28.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 28\" width=\"213\" height=\"71\" \/><br \/>\nAnswer:<br \/>\n9 + 10 = 19, We use double 9 + 9<\/p>\n<p>Explanation:<br \/>\nAs the first addend is 9 and we know the double is 9 + 9 ,<br \/>\nSo 9 + 9 = 18 , The number 10 is one more than 9,<br \/>\nSo we can write 10 as 9 + 1, The required sum is one more than double,<br \/>\n18 + 1 =19, Sum is 19, therefore 9 + 10 = 19, Double plus 1.<br \/>\nHere we have use double 9 + 9<\/p>\n<p>9 + 8 = ____17____<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24076\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-29.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 29\" width=\"212\" height=\"70\" \/><br \/>\nAnswer:<br \/>\n9 + 8 = 17, We use double 9 + 9<\/p>\n<p>Explanation:<br \/>\nAs the first addend is 9 and we know the double is 9 + 9,<br \/>\n9 + 9 = 18 , The number 8 is one less than 9,<br \/>\nSo we can write 8 as 9 &#8211; 1, The required sum is one less than double,<br \/>\n18 &#8211; 1 = 17, Sum is 17, therefore 9 + 8 = 17, Double minus 1.<br \/>\nWe have use double 9 + 9<\/p>\n<p>Find the sum. Write the double you used.<\/p>\n<p>Question 2.<br \/>\n10 + 9 = ____19_____<\/p>\n<p>____10+10___ -\u25cb ___1____ = __19_____<br \/>\nAnswer:<br \/>\n10 + 9 = 19, we use double 10 + 10,<\/p>\n<p>Explanation:<br \/>\nAs the first addend is 10 and we know the double is 10 + 10,<br \/>\n10 + 10 = 20 , The number 9 is one less than 10,<br \/>\nSo we can write 9 as 10 &#8211; 1, The required sum is one less than double,<br \/>\n20 &#8211; 1 = 19, Sum is 19, therefore 10 + 9 = 17, Double minus 1.<br \/>\nWe have use double 10 + 10 .<\/p>\n<p>Question 3.<br \/>\n7 + 8 = ____15_____<\/p>\n<p>_7_+ 7_+____ \u25cb __1_____ = ___15___<br \/>\nAnswer:<br \/>\n7 + 8 = 15, We use double 7 + 7<br \/>\nExplanation:<br \/>\nAs the first addend is 7 and we know the double is 7 +7\u00a0 ,<br \/>\nSo 7 + 7 = 14 , The number 8 is one more than 7,<br \/>\nSo we can write 8 as 7 + 1, The required sum is one more than double,<br \/>\n14 + 1 =15, Sum is 15, therefore 7 + 8 = 15, Double plus 1.<br \/>\nWe use double 7 + 7.<\/p>\n<p>Question 4.<br \/>\n<strong>DIG DEEPER!<\/strong><br \/>\nCircle two ways you can solve 8 + 9. Show how you know.<br \/>\n8 + 8 and 1 more<br \/>\n8 + 8 and 1 less<br \/>\n9 + 9 and 1 more<br \/>\n9 + 9 and 1 less<br \/>\nAnswer:<br \/>\nTo solve 8 + 9 the two ways\u00a0 which we can solve are<br \/>\n8 + 8 and 1 more and other is 9 + 9 and 1 less.<br \/>\n<a href=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-10.bmp\"><img loading=\"lazy\" class=\"alignnone size-full wp-image-27782\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-10.bmp\" alt=\"\" width=\"224\" height=\"164\" \/><\/a><br \/>\nExplanation:<br \/>\nWe know 8 + 9 = 17 now we will see which way we can solve,<br \/>\n1. 8 + 8 and 1 more means , it is 16 + 1 which is equal to 17,<br \/>\nSimilar to 8 + 9 = 17 , therefore we can solve with 8 + 8 and 1 more .<br \/>\n2. 8 + 8 and 1 less means it is 16 &#8211; 1 which is 15,<br \/>\nAs 15 is not equal to 8 + 9 = 17, So 8 + 8 and 1 less way we will not solve 8 + 9 .<br \/>\n3. 9 + 9 and 1 more means 18 + 1 = 19 , here this is not equal to 17,<br \/>\nSo by 9 + 9 and 1 more way we will not solve for 8 + 9.<br \/>\n4. 9 + 9 and 1 less means 18 -1 = 17 which is equal to sum of 8 + 9\u00a0 ,<br \/>\nSo 9 + 9 and 1 less way we will solve 8 + 9.<br \/>\nTherefore to solve 8 + 9 the two ways which we can solve are<br \/>\n8 + 8 and 1 more and other is 9 + 9 and 1 less.<\/p>\n<p>Question 5.<br \/>\n<strong>Modeling Real Life<\/strong><br \/>\nThere are 6 balls. There is 1 more toy hoop than balls. How many toys are there?<br \/>\nWhich doubles can you use to find the sum?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24075\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-30.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 30\" width=\"115\" height=\"65\" \/><br \/>\n7 + 7\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a08 + 8\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 6 + 6<\/p>\n<p>___13_____ toys<br \/>\nAnswer:<br \/>\nThere are 13 toys in total,<br \/>\nWe use doubles 6 + 6 to find the sum 6 + 7 = 13.<\/p>\n<p>Explanation:<br \/>\nGiven there are 6 balls and there is\u00a0 1 more toy hoop than balls means<br \/>\nnumber of toy hoops =\u00a0 6 + 1 = 7, so total number of toys are<br \/>\n6+ 7 = 6+ 6 + 1 = 13, Here we have used doubles 6 + 6.<br \/>\nTherefore to find the sum we use doubles 6 + 6 and the sum is 6 + 7 = 13.<\/p>\n<p><strong>Review &amp; Refresh<\/strong><\/p>\n<p>Use the picture to write an equation.<\/p>\n<p>Question 6.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24074\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-31.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 31\" width=\"261\" height=\"121\" \/><br \/>\n____7____ &#8211; ___1____ = ____6____<br \/>\nAnswer:<br \/>\nEquation is 7 &#8211; 1 = 6<\/p>\n<p>Explanation:<br \/>\nBy seeing the picture there are total 7 children in the picture,<br \/>\n6 children are sitting and reading books and one boy with bag on shoulder&#8217;s is<br \/>\nwalking away from other children, So we write the equation as 7 -1 = 6.<\/p>\n<p>Question 7.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24073\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-32.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 32\" width=\"263\" height=\"122\" \/><br \/>\n____5____ &#8211; ___1____ = ___4_____<br \/>\nAnswer:<br \/>\nEquation is 5 &#8211; 1 = 4<\/p>\n<p>Explanation:<br \/>\nBy seeing the picture there are total 5 children ,<br \/>\nin them four are sitting and playing with toy,<br \/>\none boy is walking away from others,<br \/>\nSo we write the equation as 5 &#8211; 1 =4.<\/p>\n<h3><a id=\"Lesson_4.3_Count_on_to_Add_within_20\"><\/a>Lesson 4.3 Count on to Add within 20<\/h3>\n<p><strong>Explore and Grow<\/strong><\/p>\n<p>Model the story.<\/p>\n<p>There are 8 coins in a piggy bank. You put in 5 more. How many coins are in the bank now?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24264\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-33.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 33\" width=\"530\" height=\"499\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-33.png 530w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-33-300x282.png 300w\" sizes=\"(max-width: 530px) 100vw, 530px\" \/><br \/>\nAnswer:<br \/>\nThere are 13 coins in the piggy bank.<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28276 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-13.bmp\" alt=\"\" width=\"530\" height=\"499\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-13.bmp 530w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-13-300x282.jpg 300w\" sizes=\"(max-width: 530px) 100vw, 530px\" \/><\/p>\n<p>Explanation:<br \/>\nGiven there are 8 coins in a piggy bank and I have put 5 more means,<br \/>\nwe start from 8 and move 5 units from 8 on number line we get 13, 8 + 5 = 13,<br \/>\nThere are total 13 coins in the piggy bank.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 1.<br \/>\n8 + 4 = _____12_____<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24263\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-34.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 34\" width=\"524\" height=\"49\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-34.png 524w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-34-300x28.png 300w\" sizes=\"(max-width: 524px) 100vw, 524px\" \/><br \/>\nAnswer:<br \/>\n8 + 4 = 12<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28278 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-14.bmp\" alt=\"\" width=\"599\" height=\"201\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-14.bmp 599w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-14-300x101.jpg 300w\" sizes=\"(max-width: 599px) 100vw, 599px\" \/><\/p>\n<p>Explanation:<br \/>\nFirst we start from 8 and move 4 units we get 12 on the number line,<br \/>\nSo sum is 8 + 4 = 12 .<\/p>\n<p>Question 2.<br \/>\n5 + 10 = ___15______<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24262\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-35.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 35\" width=\"525\" height=\"48\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-35.png 525w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-35-300x27.png 300w\" sizes=\"(max-width: 525px) 100vw, 525px\" \/><br \/>\nAnswer:<br \/>\n5 + 10 = 15<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28280 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-15.bmp\" alt=\"\" width=\"599\" height=\"201\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-15.bmp 599w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-15-300x101.jpg 300w\" sizes=\"(max-width: 599px) 100vw, 599px\" \/><br \/>\nExplanation:<br \/>\nFirst we start from 5 and move 10 units we get 15 on the number line,<br \/>\nSo sum is 5 + 10 = 15 .<\/p>\n<p><strong>Apply and Grow: Practice<\/strong><\/p>\n<p>Question 3.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24261\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 36\" width=\"527\" height=\"46\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36.png 527w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36-300x26.png 300w\" sizes=\"(max-width: 527px) 100vw, 527px\" \/><br \/>\n6 + 8 = _____14_____<br \/>\nAnswer:<br \/>\n6 + 8 = 14<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28323 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-16.bmp\" alt=\"\" width=\"599\" height=\"201\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-16.bmp 599w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-16-300x101.jpg 300w\" sizes=\"(max-width: 599px) 100vw, 599px\" \/><br \/>\nExplanation:<br \/>\nFirst we start from 6 and move 8 units we get 14 on the number line,<br \/>\nSo sum is 6 + 8 = 14 .<\/p>\n<p>Question 4.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24261\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 36\" width=\"527\" height=\"46\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36.png 527w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36-300x26.png 300w\" sizes=\"(max-width: 527px) 100vw, 527px\" \/><br \/>\n12 + 5 = __17______<br \/>\nAnswer:<br \/>\n12 + 5 = 17<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28328 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-17.bmp\" alt=\"\" width=\"599\" height=\"201\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-17.bmp 599w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-17-300x101.jpg 300w\" sizes=\"(max-width: 599px) 100vw, 599px\" \/><br \/>\nExplanation:<br \/>\nFirst we start from 12 and move 5 units we get 17 on the number line,<br \/>\nSo sum is 12 + 5 = 17 .<\/p>\n<p>Question 5.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24261\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 36\" width=\"527\" height=\"46\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36.png 527w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36-300x26.png 300w\" sizes=\"(max-width: 527px) 100vw, 527px\" \/><br \/>\n7 + 8 = ___15______<br \/>\nAnswer:<br \/>\n7 + 8 = 15<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28330 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-18.bmp\" alt=\"\" width=\"599\" height=\"201\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-18.bmp 599w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-18-300x101.jpg 300w\" sizes=\"(max-width: 599px) 100vw, 599px\" \/><br \/>\nExplanation:<br \/>\nFirst we start from 7 and move 8 units we get 15 on the number line,<br \/>\nSo sum is 7 + 8 = 15 .<\/p>\n<p>Question 6.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24261\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 36\" width=\"527\" height=\"46\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36.png 527w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36-300x26.png 300w\" sizes=\"(max-width: 527px) 100vw, 527px\" \/><br \/>\n10 + 9 = ___19_____<br \/>\nAnswer:<br \/>\n10 + 9 = 19<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28337 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-19.bmp\" alt=\"\" width=\"599\" height=\"201\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-19.bmp 599w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-19-300x101.jpg 300w\" sizes=\"(max-width: 599px) 100vw, 599px\" \/><\/p>\n<p>Explanation:<br \/>\nFirst we start from 10 and move 9 units we get 19 on the number line,<br \/>\nSo sum is\u00a0 10 + 9 = 19 .<\/p>\n<p>Question 7.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24261\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 36\" width=\"527\" height=\"46\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36.png 527w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36-300x26.png 300w\" sizes=\"(max-width: 527px) 100vw, 527px\" \/><br \/>\n____11___ = 0 + 11<br \/>\nAnswer:<br \/>\n11 = 0 + 11 or 0 + 11 = 11<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28340 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-20.bmp\" alt=\"\" width=\"599\" height=\"201\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-20.bmp 599w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-20-300x101.jpg 300w\" sizes=\"(max-width: 599px) 100vw, 599px\" \/><\/p>\n<p>Explanation:<br \/>\nFirst we start from 0 and move 11 units we get 11 on the number line,<br \/>\nSo sum is 11= 0 + 11 or 0 + 11 = 11.<\/p>\n<p>Question 8.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24261\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 36\" width=\"527\" height=\"46\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36.png 527w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-36-300x26.png 300w\" sizes=\"(max-width: 527px) 100vw, 527px\" \/><br \/>\n___13_____ = 4 + 9<br \/>\nAnswer:<br \/>\n13 = 4 + 9<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28496 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-1-1.bmp\" alt=\"\" width=\"633\" height=\"207\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-1-1.bmp 633w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-1-1-300x98.jpg 300w\" sizes=\"(max-width: 633px) 100vw, 633px\" \/><\/p>\n<p>Explanation:<br \/>\nFirst we start from 4 and move 9 units we get 13 on the number line,<br \/>\nSo sum is 13= 4 + 9\u00a0 or 4 + 9 = 13.<\/p>\n<p>Question 9.<br \/>\n<strong>MP Structure<\/strong><br \/>\nWrite the equation shown by the number line. Then write the equation another way.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24260\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-37.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 37\" width=\"541\" height=\"150\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-37.png 541w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-37-300x83.png 300w\" sizes=\"(max-width: 541px) 100vw, 541px\" \/><br \/>\nAnswer:<br \/>\n7 + 4 = 11\u00a0 \u00a0 \u00a0or\u00a0 4 + 7 = 11 or 11 = 7 + 4<\/p>\n<p>Explanation:<br \/>\nAs shown in the number line we are starting from 7<br \/>\nand moving 4 units we get 11,<br \/>\nSo the equation is 7 + 4 = 11, we can also write\u00a0 the equation as 4 + 7 =11,<br \/>\nthere is no change in the value of sum.<br \/>\nWe get sum 11 if we add 7 and 4.<\/p>\n<p><strong>Think and Grow: Modeling Real Life<\/strong><\/p>\n<p>You have 7 train cars. Newton has 5 more than you. Descartes has 4 more than you. Who has more train cars, Newton or Descartes?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24259\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-38.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 38\" width=\"169\" height=\"168\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-38.png 169w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-38-150x150.png 150w\" sizes=\"(max-width: 169px) 100vw, 169px\" \/><br \/>\nModel:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24258\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-39.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 39\" width=\"524\" height=\"52\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-39.png 524w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-39-300x30.png 300w\" sizes=\"(max-width: 524px) 100vw, 524px\" \/><\/p>\n<p><img loading=\"lazy\" class=\"alignnone wp-image-28497 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-2.bmp\" alt=\"\" width=\"633\" height=\"207\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-2.bmp 633w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-2-300x98.jpg 300w\" sizes=\"(max-width: 633px) 100vw, 633px\" \/><\/p>\n<p>Equations:<br \/>\nNewton\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0Descartes<br \/>\n7 + 5 = 12\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 7 + 4 = 11<\/p>\n<p>Who has more?\u00a0 \u00a0 \u00a0 \u00a0 \u00a0<span style=\"text-decoration: underline;\">Newton<\/span>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0<span style=\"text-decoration: underline;\">Descartes<br \/>\n<\/span>Newton has more trains.<\/p>\n<p>Explanation:<br \/>\nGiven I have 7 trains, Newton has 5 more than you,<br \/>\nSo the equation is 7 + 5 = 12, Newton has 12 trains,<br \/>\nand Descartes has 4 more than me , the equation is<br \/>\n7 + 4 = 11, Descartes has 11 trains. Now we compare with<br \/>\nNewton and Descartes so in between 12 and 11 we compare,<br \/>\nas 12 is more or greater than 11, means Newton has more trains = 12.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 10.<br \/>\nYou have 6 comic books. Newton has 5 more than you. Descartes has 6 more than you. Who has more comic books, Newton or Descartes?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24257\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-40.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 40\" width=\"212\" height=\"105\" \/><br \/>\nModel:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24258\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-39.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 39\" width=\"524\" height=\"52\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-39.png 524w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-39-300x30.png 300w\" sizes=\"(max-width: 524px) 100vw, 524px\" \/><br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28499 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-3.bmp\" alt=\"\" width=\"633\" height=\"207\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-3.bmp 633w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-3-300x98.jpg 300w\" sizes=\"(max-width: 633px) 100vw, 633px\" \/><br \/>\nEquations:<br \/>\nNewton\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0Descartes<br \/>\n6 + 5 = 11\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 6 + 6 = 12<\/p>\n<p>Who has more?\u00a0 \u00a0 \u00a0 \u00a0 \u00a0<span style=\"text-decoration: underline;\">Newton<\/span>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0<span style=\"text-decoration: underline;\">Descartes<br \/>\n<\/span>Descartes has more comic books.<br \/>\n<span style=\"text-decoration: underline;\"><br \/>\n<\/span>Explanation:<br \/>\nGiven I have 6 comic books , Newton has 5 more than you,<br \/>\nSo the equation is 6 + 5 = 11, Newton has 11 comic books,<br \/>\nand Descartes has 6 more than me , the equation is<br \/>\n6 + 6 = 12, Descartes has 12 comic books. Now we compare with<br \/>\nNewton and Descartes so in between 11 and 12 we compare,<br \/>\nas 12 is more or greater than 11, means Descartes has more comic books = 12.<\/p>\n<h3><a id=\"Count_on_to_Add_within_20_Practice_4.3\"><\/a>Count on to Add within 20 Practice 4.3<\/h3>\n<p>Question 1.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24256\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-41.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 41\" width=\"522\" height=\"48\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-41.png 522w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-41-300x28.png 300w\" sizes=\"(max-width: 522px) 100vw, 522px\" \/><br \/>\n10 + 7 = ___17_______<br \/>\nAnswer:<br \/>\n10 + 7 = 17<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28500 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-4.bmp\" alt=\"\" width=\"633\" height=\"207\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-4.bmp 633w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-4-300x98.jpg 300w\" sizes=\"(max-width: 633px) 100vw, 633px\" \/><br \/>\nExplanation:<br \/>\nFirst we start from 10 and move 7 units we get 17 on the number line,<br \/>\nSo sum is 10 + 7 = 17.<\/p>\n<p>Question 2.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24256\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-41.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 41\" width=\"522\" height=\"48\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-41.png 522w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-41-300x28.png 300w\" sizes=\"(max-width: 522px) 100vw, 522px\" \/><br \/>\n8 + 9 = ____17_____<br \/>\nAnswer:<br \/>\n8 + 9 = 17<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28502 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-5.bmp\" alt=\"\" width=\"633\" height=\"207\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-5.bmp 633w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-chp-5-300x98.jpg 300w\" sizes=\"(max-width: 633px) 100vw, 633px\" \/><br \/>\nExplanation:<br \/>\nFirst we start from 8 and move 9 units we get 17 on the number line,<br \/>\nSo sum is 10 + 7 = 17.<\/p>\n<p>Question 3.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24256\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-41.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 41\" width=\"522\" height=\"48\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-41.png 522w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-41-300x28.png 300w\" sizes=\"(max-width: 522px) 100vw, 522px\" \/><br \/>\n_____15_____ = 6 + 9<br \/>\nAnswer:<br \/>\n6 + 9 = 15 or 15 = 6 + 9<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28504 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-6.bmp\" alt=\"\" width=\"633\" height=\"207\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-6.bmp 633w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-6-300x98.jpg 300w\" sizes=\"(max-width: 633px) 100vw, 633px\" \/><br \/>\nExplanation:<br \/>\nFirst we start from 6 and move 9 units we get 15 on the number line,<br \/>\nSo sum is 6 + 9 = 15 or 15 = 6 + 9.<\/p>\n<p>Question 4.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24256\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-41.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 41\" width=\"522\" height=\"48\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-41.png 522w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-41-300x28.png 300w\" sizes=\"(max-width: 522px) 100vw, 522px\" \/><br \/>\n______16_____ = 12 + 4<br \/>\nAnswer:<br \/>\n16= 12 + 4 or 12 + 4 = 16<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28505 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-7.bmp\" alt=\"\" width=\"633\" height=\"207\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-7.bmp 633w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-7-300x98.jpg 300w\" sizes=\"(max-width: 633px) 100vw, 633px\" \/><\/p>\n<p>Explanation:<br \/>\nFirst we start from 12 and move 4 units we get 16 on the number line,<br \/>\nSo sum is\u00a0 12 + 4 = 16 or 16 = 12 + 4.<\/p>\n<p>Question 5.<br \/>\n<strong>MP Structure<\/strong><br \/>\nWrite the equation shown by the number line. Then write the equation another way.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24255\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-42.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 42\" width=\"536\" height=\"136\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-42.png 536w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-42-300x76.png 300w\" sizes=\"(max-width: 536px) 100vw, 536px\" \/><br \/>\nAnswer:<br \/>\n5 + 8 = 13\u00a0 or\u00a0 8 + 5 = 13 or 13 = 5 + 8<\/p>\n<p>Explanation:<br \/>\nAs shown in the number line we are starting from 5<br \/>\nand moving 8 units we get 13,<br \/>\nSo the equation is 5 + 8 = 13, we can also write\u00a0 the equation as 8 + 5 =13,<br \/>\nthere is no change in the value of sum.<br \/>\nWe get sum 13 if we add 5 and 8.<\/p>\n<p>Question 6.<br \/>\n<strong>Modeling Real Life<\/strong><br \/>\nYou have 11 toys. Newton has 3 more than you. Descartes has 6 more than you. Who has more toys, Newton or Descartes?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24254\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-43.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 43\" width=\"94\" height=\"78\" \/><br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24253\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-44.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 44\" width=\"529\" height=\"117\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-44.png 529w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-44-300x66.png 300w\" sizes=\"(max-width: 529px) 100vw, 529px\" \/><br \/>\nAnswer:<br \/>\nEquations:\u00a0 \u00a0 \u00a0Newton\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0Descartes<br \/>\n11 + 3 = 14\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 11 + 6 = 17<br \/>\nDescartes has more toys than Newton<br \/>\n<span style=\"text-decoration: underline;\"><img loading=\"lazy\" class=\"alignnone wp-image-28508 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-8.bmp\" alt=\"\" width=\"633\" height=\"207\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-8.bmp 633w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-8-300x98.jpg 300w\" sizes=\"(max-width: 633px) 100vw, 633px\" \/><br \/>\n<\/span>Explanation:<br \/>\nGiven I have 11 toys , Newton has 3 more than you,<br \/>\nSo the equation is 11 + 3 = 14, Newton has 14 toys,<br \/>\nand Descartes has 6 more than me , the equation is<br \/>\n11 + 6 = 17, Descartes has 17 toys. Now we compare with<br \/>\nNewton and Descartes so in between 14 and 17 toys if\u00a0 we compare<br \/>\nwe get 17 is more or greater than 14, means Descartes has more toys = 17.<\/p>\n<p><strong>Review &amp; Refresh<\/strong><\/p>\n<p>Question 7.<br \/>\nCircle the triangle. Draw a rectangle around the hexagon.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24252\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-45.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 45\" width=\"539\" height=\"96\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-45.png 539w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-45-300x53.png 300w\" sizes=\"(max-width: 539px) 100vw, 539px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28512 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-9.bmp\" alt=\"\" width=\"633\" height=\"207\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-9.bmp 633w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-9-300x98.jpg 300w\" sizes=\"(max-width: 633px) 100vw, 633px\" \/><br \/>\nExplanation:<br \/>\nWe know triangle means a closed, two-dimensional shape with three straight sides.<br \/>\nIn shapes given in figure we have triangle in green so we will circle it,<br \/>\nand we know hexagon can be defined as a polygon with six sides.<br \/>\nIn shapes given in the figure we have hexagon in yellow,<br \/>\nSo we draw a rectangle around the hexagon.<\/p>\n<p>Question 8.<br \/>\nCircle the cube. Draw a rectangle around the sphere.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24251\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-46.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 46\" width=\"536\" height=\"93\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-46.png 536w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-46-300x52.png 300w\" sizes=\"(max-width: 536px) 100vw, 536px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28518 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-10.bmp\" alt=\"\" width=\"633\" height=\"207\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-10.bmp 633w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-10-300x98.jpg 300w\" sizes=\"(max-width: 633px) 100vw, 633px\" \/><br \/>\nExplanation:<br \/>\nCube means a symmetrical three-dimensional shape,<br \/>\neither solid or hollow, contained by six equal squares,<br \/>\nIn figure we have cube in purple so we circle the cube.<br \/>\nSphere means a round solid figure, or its surface,<br \/>\nwith every point on its surface equidistant from its center.<br \/>\nIn the shapes given in figure we have sphere in yellow,<br \/>\nSo we draw a rectangle around hexagon.<\/p>\n<h3><a id=\"Lesson_4.4_Add_Three_Numbers\"><\/a>Lesson 4.4 Add Three Numbers<\/h3>\n<p><strong>Explore and Grow<\/strong><\/p>\n<p>Use linking cubes to model the story.<\/p>\n<p>You have 5 red pencils, 4 yellow pencils, and 3 blue pencils. How many pencils do you have in all?<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-24295\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-47.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 47\" width=\"258\" height=\"221\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-47.png 594w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-47-300x257.png 300w\" sizes=\"(max-width: 258px) 100vw, 258px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28523 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-11.bmp\" alt=\"\" width=\"619\" height=\"391\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-11.bmp 619w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-11-300x189.jpg 300w\" sizes=\"(max-width: 619px) 100vw, 619px\" \/><\/p>\n<p>Explanation:<br \/>\nGiven 5 red pencils , 4 yellow pencils\u00a0 and 3 blue pencils,<br \/>\na. Now by using linking the cubes first we link with 5 red and 4 yellow pencils<br \/>\nwe get 5 + 4 = 9 pencils now we link with 3 blue pencils 9 + 3 = 12 pencils.<br \/>\nb. Now by using linking the cubes first we link with 4 yellow pencils and 3 blue pencils<br \/>\nwe get 4 + 3 = 7 pencils now we link with 5 red pencils 7 + 5 = 12 pencils.<br \/>\nc. Now by using linking the cubes first we link with 5 red and 3 blue pencils<br \/>\nwe get 5 + 3 = 8 pencils now we link with 4 yellow pencils 8 + 4 = 12 pencils.<br \/>\nIn all we have 12 pencils.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 1.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24294\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-48.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 48\" width=\"522\" height=\"120\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-48.png 522w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-48-300x69.png 300w\" sizes=\"(max-width: 522px) 100vw, 522px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28527 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-12.bmp\" alt=\"\" width=\"592\" height=\"223\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-12.bmp 592w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-12-300x113.jpg 300w\" sizes=\"(max-width: 592px) 100vw, 592px\" \/><br \/>\nExplanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 2 + 5 = 7 and now we add 7+ 6 we get 13.<br \/>\nb. Here we add 5 + 6 =11, now we add 11 + 2 =13<br \/>\nc. Now here we add first 2 with 6 we get 8 to 8 we add 5<br \/>\nwe will get 8 + 5 = 13, So we get sum as 13.<\/p>\n<p>Question 2.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24293\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-49.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 49\" width=\"522\" height=\"115\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-49.png 522w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-49-300x66.png 300w\" sizes=\"(max-width: 522px) 100vw, 522px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28528 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-13.bmp\" alt=\"\" width=\"592\" height=\"223\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-13.bmp 592w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-13-300x113.jpg 300w\" sizes=\"(max-width: 592px) 100vw, 592px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 4 + 4 = 8 and now we add 8+ 3 we get 11.<br \/>\nb. Here we add 3 + 4 =7, now we add 7 + 4 =11<br \/>\nc. Now here we add first 4 with 3 we get 7 to 7 we add 4<br \/>\nwe will get 7 + 4 = 11, So we get sum as 11.<\/p>\n<p><strong>Apply and Grow: Practice<\/strong><\/p>\n<p>Question 3.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24292\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-50.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 50\" width=\"527\" height=\"123\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-50.png 527w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-50-300x70.png 300w\" sizes=\"(max-width: 527px) 100vw, 527px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28529 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-14.bmp\" alt=\"\" width=\"592\" height=\"223\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-14.bmp 592w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-14-300x113.jpg 300w\" sizes=\"(max-width: 592px) 100vw, 592px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 3 + 3 = 6 and now we add 6+ 5 we get 11.<br \/>\nb. Here we add 3 + 5 =8, now we add 8 + 3 =11<br \/>\nc. Now here we add first 5 with 3 we get 8 to 8 we add 3<br \/>\nwe will get 8 + 3 = 11, So we get sum as 11.<\/p>\n<p>Question 4.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24291\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-51.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 51\" width=\"165\" height=\"82\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28532 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-15.bmp\" alt=\"\" width=\"592\" height=\"223\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-15.bmp 592w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-15-300x113.jpg 300w\" sizes=\"(max-width: 592px) 100vw, 592px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 3 + 1 = 4 and now we add 4+ 2 we get 6.<br \/>\nb. Here we add 1 + 2 =3, now we add 3 + 3 =6,<br \/>\nc. Now here we add first 3 with 2 we get 5 to 5 we add 1<br \/>\nwe will get 5 + 1 = 6, So we get sum as 6.<\/p>\n<p>Question 5.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24290\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-52.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 52\" width=\"161\" height=\"80\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28535 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-16.bmp\" alt=\"\" width=\"592\" height=\"223\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-16.bmp 592w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-16-300x113.jpg 300w\" sizes=\"(max-width: 592px) 100vw, 592px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 7 + 5 = 12 and now we add 12+ 5 we get 17.<br \/>\nb. Here we add 5 + 5 =10, now we add 10 + 7 = 17,<br \/>\nc. Now here we add first 7 with 5 we get 12 to 12 we add 5<br \/>\nwe will get 12 + 5 = 17, So we get sum as 17.<\/p>\n<p>Question 6.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24289\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-53.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 53\" width=\"165\" height=\"79\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28536 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-17.bmp\" alt=\"\" width=\"575\" height=\"171\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-17.bmp 575w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-17-300x89.jpg 300w\" sizes=\"(max-width: 575px) 100vw, 575px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 4 + 5 = 9 and now we add 9 + 2 we get 11.<br \/>\nb. Here we add 5 + 2 = 7, now we add 7 + 4 = 11,<br \/>\nc. Now here we add first 4 with 2 we get 6 to 6 we add 5<br \/>\nwe will get 6 + 5 = 11, So we get sum as 11.<\/p>\n<p>Question 7.<br \/>\n7 + 8 + 1 = _________<br \/>\nAnswer:<br \/>\n7 + 8 +1 = 16<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28537 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-19.bmp\" alt=\"\" width=\"592\" height=\"223\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-19.bmp 592w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-19-300x113.jpg 300w\" sizes=\"(max-width: 592px) 100vw, 592px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 7 + 1 = 8 and now we add 8 + 8 we get 16.<br \/>\nb. Here we add 7 + 8 = 15, now we add 15 + 1 = 16,<br \/>\nc. Now here we add first 8 with 1 we get 9 to 9 we add 7<br \/>\nwe will get 9 + 7 = 16, So we get sum as 16.<\/p>\n<p>Question 8.<br \/>\n8 + 6 + 2 = _________<br \/>\nAnswer:<br \/>\n8 + 6 + 2 = 16<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28539 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-20.bmp\" alt=\"\" width=\"592\" height=\"223\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-20.bmp 592w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-20-300x113.jpg 300w\" sizes=\"(max-width: 592px) 100vw, 592px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 8 + 2 = 10 and now we add 10 + 6 we get 16.<br \/>\nb. Here we add 8 + 6 = 14, now we add 14 + 2 = 16,<br \/>\nc. Now here we add first 6 with 2 we get 8 to 8 we add<br \/>\n8 we will get 8 + 8 = 16, So we get sum as 16.<\/p>\n<p>Question 9.<br \/>\n4 + 9 + 4 = __________<br \/>\nAnswer:<br \/>\n4 + 9 + 4 = 17<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28540 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-21.bmp\" alt=\"\" width=\"592\" height=\"223\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-21.bmp 592w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-21-300x113.jpg 300w\" sizes=\"(max-width: 592px) 100vw, 592px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 4 + 4 = 8 and now we add 8 + 9 we get 17.<br \/>\nb. Here we add 4 + 9 = 13, now we add 13 + 4 = 17,<br \/>\nc. Now here we add first 9 with 4 we get 13 to 13 we add 4<br \/>\nwe will get 13 + 4 = 17, So we get sum as 17.<\/p>\n<p>Question 10.<br \/>\n<strong>DIG DEEPER<\/strong><br \/>\nComplete the number puzzle so that each branch has a sum of 14.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24288\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-54.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 54\" width=\"496\" height=\"195\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-54.png 496w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-54-300x118.png 300w\" sizes=\"(max-width: 496px) 100vw, 496px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28541 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-22.bmp\" alt=\"\" width=\"575\" height=\"195\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-22.bmp 575w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-22-300x102.jpg 300w\" sizes=\"(max-width: 575px) 100vw, 575px\" \/><br \/>\nExplanation:<br \/>\nLet us take the missing number as X, Y Z, P<br \/>\nWe take 6 + 1 + ___X___ = 14 , means X = 7 + X = 14,<br \/>\ntherefore X = 14 &#8211; 7 = 7, So 6 + 1 + 7 = 14,<br \/>\nNext\u00a0 Y, 5 + Y + 6 = 14 , 11 + Y = 14 , Y = 14 -11,<br \/>\nWe get Y = 3,Making 5 + 3 + 6 = 14<br \/>\nNow Z, 6 + 7 + Z = 14, 13 + Z = 14, Z = 14 &#8211; 13,<br \/>\nZ = 1 Making 6 + 7 + 1 = 14<br \/>\nNow P, 4 + P + 3 = 14, 7 + P = 14 ,P = 14 &#8211; 7,<br \/>\nWe get P = 7 making\u00a0 4 + 7 + 3 = 14.<\/p>\n<p><strong>Think and Grow: Modeling Real Life<\/strong><\/p>\n<p>You have 6 goldfish, 7 minnows, and 6 guppies. Will the tank hold all of your fish?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24287\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-55.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 55\" width=\"185\" height=\"92\" \/><br \/>\nEquation:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24286\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-56.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 56\" width=\"262\" height=\"76\" \/><\/p>\n<p>Show how you know:<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28550 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-23.bmp\" alt=\"\" width=\"374\" height=\"114\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-23.bmp 374w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-23-300x91.jpg 300w\" sizes=\"(max-width: 374px) 100vw, 374px\" \/><br \/>\nExplanation:<br \/>\nGiven I have 6 goldfish, 7 minnows and 6 guppies, Total Number of<br \/>\nFishes with me are\u00a0 6 + 7 + 6 = 19 , No the tank can not hold<br \/>\nall of fishes as given in the figure a tank can hold 15 Fish and<br \/>\nI have 19 which are more than 15 ,<br \/>\nNo, it is not possible for the tank to hold 19 Fish.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 11.<br \/>\nYou have 2 lovebirds, 4 canaries, and 3 finches. Will the cage hold all of your birds?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24285\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-57.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 57\" width=\"137\" height=\"194\" \/><br \/>\nEquation:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24284\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-58.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 58\" width=\"259\" height=\"76\" \/><\/p>\n<p>Show how you know:<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28551 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-24.bmp\" alt=\"\" width=\"309\" height=\"128\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-24.bmp 309w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-24-300x124.jpg 300w\" sizes=\"(max-width: 309px) 100vw, 309px\" \/><\/p>\n<p>Explanation:<br \/>\nGiven I have 2 lovebirds, 4 canaries, and 3 finches ,<br \/>\nTotal Number of birds I have are 2 + 4 + 3 = 9,<br \/>\nNow as shown in the picture a cage can holds 10 birds,<br \/>\nWe have total 9 birds which is less than 10 means,<br \/>\nYes, the cage can hold all of my birds .<\/p>\n<h3><a id=\"Add_Three_Numbers_Practice_4.4\"><\/a>Add Three Numbers Practice 4.4<\/h3>\n<p>Question 1.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24283\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-59.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 59\" width=\"519\" height=\"121\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-59.png 519w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-59-300x70.png 300w\" sizes=\"(max-width: 519px) 100vw, 519px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28553 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-25.bmp\" alt=\"\" width=\"519\" height=\"128\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-25.bmp 519w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-25-300x74.jpg 300w\" sizes=\"(max-width: 519px) 100vw, 519px\" \/><br \/>\nExplanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 2 + 2 = 4 and now we add 6 + 4 we will get 10.<br \/>\nb. Here we add first 6 + 2 = 8, now we add 8 + 2 = 10,<br \/>\nc. Now here we add 6 with 2 we get 8 to 8 we add 2,<br \/>\nwe will get\u00a0 8 + 2 = 10, So we get sum as 10.<\/p>\n<p>Question 2.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24282\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-60.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 60\" width=\"165\" height=\"80\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28556 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-25-1.bmp\" alt=\"\" width=\"541\" height=\"168\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-25-1.bmp 541w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-25-1-300x93.jpg 300w\" sizes=\"(max-width: 541px) 100vw, 541px\" \/><\/p>\n<p>Question 3.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24281\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-61.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 61\" width=\"166\" height=\"81\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28557 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-26.bmp\" alt=\"\" width=\"541\" height=\"168\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-26.bmp 541w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-26-300x93.jpg 300w\" sizes=\"(max-width: 541px) 100vw, 541px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 8 + 7 = 15 and now we add 15 + 4 we will get 19.<br \/>\nb. Here we add first 7 + 4 = 11, now we add 8 + 11 = 19,<br \/>\nc. Now here we add 8 with 4 we get 12 to 12 we add 7,<br \/>\nwe will get\u00a0 12 + 7 = 19, So we get sum as 19.<\/p>\n<p>Question 4.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24280\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-62.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 62\" width=\"174\" height=\"83\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28558 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-27.bmp\" alt=\"\" width=\"592\" height=\"223\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-27.bmp 592w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-27-300x113.jpg 300w\" sizes=\"(max-width: 592px) 100vw, 592px\" \/><br \/>\nExplanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 9 + 1 = 10 and now we add 10 + 10 we will get 20.<br \/>\nb. Here we add first 9 + 10 = 19, now we add 19 + 1 = 20,<br \/>\nc. Now here we add 10 with 1 we get 11 to 11 we add 9,<br \/>\nwe will get\u00a0 11 + 9 = 20, So we get sum as 20.<\/p>\n<p>Question 5.<br \/>\n3 + 4 + 5 = _________<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28560 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-28.bmp\" alt=\"\" width=\"561\" height=\"158\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-28.bmp 561w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-28-300x84.jpg 300w\" sizes=\"(max-width: 561px) 100vw, 561px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 3 + 5 = 8 and now we add 8 + 4 we will get 12.<br \/>\nb. Here we add first 3 + 4 = 7, now we add\u00a0 7 and 5 as 7 + 5 = 12,<br \/>\nc. Now here we add 4 with 5 we get 9 to 9 we add 3,<br \/>\nwe will get\u00a0 3 + 9 = 12, So we get sum as 12.<\/p>\n<p>Question 6.<br \/>\n7 + 5 + 5 = ________<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28561 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-29.bmp\" alt=\"\" width=\"592\" height=\"223\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-29.bmp 592w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-29-300x113.jpg 300w\" sizes=\"(max-width: 592px) 100vw, 592px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 7 + 5 = 12 and now we add 12 + 5 we will get 17.<br \/>\nb. Here we add first 7 + 5 = 12, now we add\u00a0 12 and 5 as 12 + 5 = 17,<br \/>\nc. Now here we add 5 and 5 we get 10, we add 7 to 10,<br \/>\nwe will get\u00a0 7 + 10 = 17, So we get sum as 17.<\/p>\n<p>Question 7.<br \/>\n8 + 4 + 8 = ________<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28562 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-30.bmp\" alt=\"\" width=\"592\" height=\"223\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-30.bmp 592w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-30-300x113.jpg 300w\" sizes=\"(max-width: 592px) 100vw, 592px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 8 + 8 = 16 and now we add 16 + 4 we will get 20.<br \/>\nb. Here we add first 8 + 4 = 12, now we add 12 and 8 as 12 + 8 = 20,<br \/>\nc. Now here we add 4 with 8 we get 12 ,we add 8 to 12,<br \/>\nwe will get\u00a0 8 + 12 = 20, So we get sum as 20.<\/p>\n<p>Question 8.<br \/>\n<strong>DIG DEEPER!<\/strong><br \/>\nComplete the number puzzle so that each branch has the sum of 13.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24279\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-63.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 63\" width=\"502\" height=\"198\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-63.png 502w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-63-300x118.png 300w\" sizes=\"(max-width: 502px) 100vw, 502px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28563 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-31.bmp\" alt=\"\" width=\"592\" height=\"223\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-31.bmp 592w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-31-300x113.jpg 300w\" sizes=\"(max-width: 592px) 100vw, 592px\" \/><\/p>\n<p>Explanation:<br \/>\nLet us take the missing number as X, Y Z, P<br \/>\nWe take 5 + 1 + ___X___ = 13 , means X = 6 + X = 13,<br \/>\ntherefore X = 13 &#8211; 6 = 7, So 5 + 1 + 7 = 13,<br \/>\nNext\u00a0 Y, 1 + Y + 6 = 13 , 7 + Y = 13, Y = 13 &#8211; 7,<br \/>\nWe get Y = 6,Making 1 + 6 + 6 = 13<br \/>\nNow Z, 4 + 5 + Z = 13, 9 + Z = 13, Z = 13 &#8211; 9,<br \/>\nZ = 4 Making 4 + 5 + 4 = 13<br \/>\nNow P, 7 + P + 2 = 13, 9 + P = 13 ,P = 13 &#8211; 9,<br \/>\nWe get P = 4 making\u00a0 7 + 4 + 2 = 13.<\/p>\n<p>Question 9.<br \/>\n<strong>Modeling Real Life<\/strong><br \/>\nYou have 7 white chickens, I black chicken, and 8 brown chickens. Will the chicken coop hold all of your chickens?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24278\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-64.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 64\" width=\"140\" height=\"125\" \/><br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24277\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-65.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 65\" width=\"262\" height=\"59\" \/><\/p>\n<p>Show how you know:<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28565 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-32.bmp\" alt=\"\" width=\"385\" height=\"136\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-32.bmp 385w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-32-300x106.jpg 300w\" sizes=\"(max-width: 385px) 100vw, 385px\" \/><\/p>\n<p>Explanation:<br \/>\nGiven I have 7 white chickens, 1 black chicken and 8 brown chickens,<br \/>\nTotal Number of\u00a0 chickens with me are\u00a0 7 + 1 + 8 = 16 ,<br \/>\nGiven in the figure a chicken coop can hold 15 chickens and<br \/>\nI have 16 which is more than 15.<br \/>\nNo, it is not possible for the chicken coop to hold all 16 chickens.<\/p>\n<p><strong>Review &amp; Refresh<\/strong><\/p>\n<p>Question 10.<br \/>\n5 + __5__ = 10<br \/>\nAnswer:<br \/>\n5 + 5 = 10<\/p>\n<p>Explanation:<br \/>\nLet us take the missing number as X,<br \/>\nIt is given in the equation that 5 + X = 10,<br \/>\nSo X = 10 &#8211; 5 = 5, means 5 + 5 = 10.<\/p>\n<p>Question 11.<br \/>\n10 = 6 + ___4___<br \/>\nAnswer:<br \/>\n10 = 6 + 4<\/p>\n<p>Explanation:<br \/>\nLet us take the missing number as X,<br \/>\nIt is given in the equation that 10 = 6 + X,<br \/>\nSo X = 10 &#8211; 6 = 4, means 10 = 6 + 4 .<\/p>\n<p>Question 12.<br \/>\n8 + __2___ = 10<br \/>\nAnswer:<br \/>\n8 + 2 = 10<\/p>\n<p>Explanation:<br \/>\nLet us take the missing number as X,<br \/>\nIt is given in the equation that 8 + X = 10,<br \/>\nSo X = 10 &#8211; 8 = 2, means 8 + 2 = 10.<\/p>\n<p>Question 13.<br \/>\n10 = 3 + __7___<br \/>\nAnswer:<br \/>\n10 = 3 + 7<\/p>\n<p>Explanation:<br \/>\nLet us take the missing number as X,<br \/>\nIt is given in the equation that 10 = 3 + 7,<br \/>\nSo X = 10 &#8211; 3 = 7, means 10 = 3 + 7.<\/p>\n<h3><a id=\"Lesson_4.5_Add_Three_Numbers_by_Making_a_10\"><\/a>Lesson 4.5 Add Three Numbers by Making a 10<\/h3>\n<p><strong>Explore and Grow<\/strong><\/p>\n<p>Show three ways to find a sum.<br \/>\n4 + 3 + 7 = ________<\/p>\n<p>4 + 3 + 7 = ________<\/p>\n<p>4 + 3 + 7 = ________<br \/>\nAnswer:<br \/>\n4 + 3 + 7 = 14<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28664 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-33-1.bmp\" alt=\"\" width=\"568\" height=\"152\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-33-1.bmp 568w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-33-1-300x80.jpg 300w\" sizes=\"(max-width: 568px) 100vw, 568px\" \/><\/p>\n<p>Explanation:<br \/>\nBy using the three ways we find sum,<br \/>\nWay 1. First we add 4 + 7 = 11 and now we add 11 + 3 we will get 14.<br \/>\nWay 2. Here we add first 4 + 3 = 7, now we add 7 and 7 as 7 + 7 = 14,<br \/>\nWay 3. Now here we add 3 with 7 we get 10 to 10 we add 4,<br \/>\nwe will get\u00a0 4 + 10 = 14, So we get sum as 14.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Make a 10 to add.<\/p>\n<p>Question 1.<\/p>\n<p><img loading=\"lazy\" class=\"alignnone size-full wp-image-24563\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-66.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 66\" width=\"167\" height=\"110\" \/><\/p>\n<p>Answer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28669 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-34.bmp\" alt=\"\" width=\"239\" height=\"152\" \/><br \/>\nAdd 9,1 first to make 10 then add 3, sum = 9 + 1 + 3 = 13<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 9 + 1 = 10 is equal to 10,<br \/>\nnext we add 1 +3 =4 not equal to 10, 9 + 3 = 12 which<br \/>\nis not equal to 10 ,So to make 10 we add\u00a0 9,1 first, then add 3,<br \/>\nSo the sum is 9 + 1 + 3 = 13.<\/p>\n<p>Question 2.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24562\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-67.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 67\" width=\"166\" height=\"112\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28688 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-35.bmp\" alt=\"\" width=\"239\" height=\"152\" \/><\/p>\n<p>Add 2,8 first to make 10 then add 4, sum = 4 + 2 + 8 = 14<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 4 + 2 = 6,<br \/>\n6 is not equal to 10, 2 + 8 = 10 which is equal to 10 ,<br \/>\nand now we add 4 + 8 = 12 which is not equal to 10,<br \/>\nSo to make 10 we add 2,8 first then add 4<br \/>\nSo the sum is 4 + 2 + 8 = 14.<\/p>\n<p>Question 3.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24561\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-68.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 68\" width=\"133\" height=\"128\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28692 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-36.bmp\" alt=\"\" width=\"239\" height=\"152\" \/><br \/>\nAdd 3,7 first to make 10 then add 2, sum = 2 + 3 + 7 = 12<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 2 + 3 = 5,<br \/>\n5 is not equal to 10, 3 + 7 = 10 which is equal to 10 ,<br \/>\nand now we add 2 + 7 = 9 which is not equal to 10,<br \/>\nSo to make 10 we add 3,7 first and then add 2<br \/>\nSo the sum is 2 + 3 + 7 = 12.<\/p>\n<p>Question 4.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24560\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-69.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 69\" width=\"129\" height=\"129\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28714 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-37.bmp\" alt=\"\" width=\"239\" height=\"152\" \/><br \/>\nAdd 5,5 first to make 10 then add 9, sum = 5 + 5 + 9 = 19<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 5 + 5 = 10,<br \/>\nso is equal to 10, now we add 5 + 9 = 14\u00a0 which is not equal to 10 ,<br \/>\nand now we add other 5 + 9 = 14 which is also not equal to 10,<br \/>\nSo to make 10 we add 5,5 first and then add 9,<br \/>\nSo the sum is 5 + 5 + 9 = 19.<\/p>\n<p><strong>Apply and Grow: Practice<\/strong><\/p>\n<p>Make a 10 add.<\/p>\n<p>Question 5.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24559\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-70.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 70\" width=\"168\" height=\"85\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29017 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-38-1.bmp\" alt=\"\" width=\"253\" height=\"226\" \/><br \/>\nAdd 3,7 or 7,3 first to make 10 then add 3, sum = 3 + 7 + 3 = 13<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 3 + 7 = 10,<br \/>\nso is equal to 10, now we add 7 + 3 = 10\u00a0 which is also equal to 10 ,<br \/>\nand now we add other 3 + 3 = 6 which is not equal to 10,<br \/>\nSo to make 10 we add 3,7 or 7,3 first and then add 3<br \/>\nSo the sum is 3 + 7 + 3 = 13.<\/p>\n<p>Question 6.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24558\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-71.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 71\" width=\"166\" height=\"86\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28726 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-39.bmp\" alt=\"\" width=\"240\" height=\"117\" \/><\/p>\n<p>Add 8,2 first to make 10 then add 6, sum = 8 + 6 + 2 = 16<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 8 + 6 = 14,<br \/>\n14 is not equal to 10, now we add 6 + 2 = 8\u00a0 which is not equal to 10 ,<br \/>\nand now we add 8 + 2 = 10 which is equal to 10,<br \/>\nSo to make 10 we add 8,2 first and then add 6<br \/>\nSo the sum is 8 + 6 + 2 = 16.<\/p>\n<p>Question 7.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24557\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-72.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 72\" width=\"138\" height=\"131\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28804 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-40.bmp\" alt=\"\" width=\"240\" height=\"131\" \/><\/p>\n<p>Add 6,4 first to make 10 then add 7, sum = 6 + 7 + 4 = 17<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 6 + 7 = 13,<br \/>\nIt is not equal to 10, now we add 7 + 4 = 11\u00a0 which is not equal to 10 ,<br \/>\nand now we add 6 + 4 = 10 which is equal to 10,<br \/>\nSo to make 10 we add 6,4 first then add 7<br \/>\nSo the sum is 6 + 7 + 4 = 17.<\/p>\n<p>Question 8.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24556\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-73.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 73\" width=\"129\" height=\"129\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28829 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-41.bmp\" alt=\"\" width=\"147\" height=\"132\" \/><\/p>\n<p>Add 5,5 first to make 10 then add 8, sum = 8 + 5 + 5 = 18<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 8 + 5 = 13,<br \/>\nIt is not equal to 10, now we add 5 + 5 = 10\u00a0 which equal to 10 ,<br \/>\nand now we add 8 + 5 = 13 which is not equal to 10,<br \/>\nSo to make 10 we add 5,5 first then add 8<br \/>\nSo the sum is 8 + 5 + 5 = 18.<\/p>\n<p>Question 9.<br \/>\n4 + 6 + 2 = ________<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28830 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-42.bmp\" alt=\"\" width=\"204\" height=\"134\" \/><\/p>\n<p>Add 4,6 first to make 10 then add 2, sum = 4 + 6 + 2 = 12<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 4 + 6 = 10,<br \/>\nwhich is equal to 10, now we add 6 + 2 = 8\u00a0 which is not equal to 10 ,<br \/>\nand now we add 4 + 2 = 6 which is not equal to 10,<br \/>\nSo to make 10 we add 4,6 first then add 2<br \/>\nSo the sum is 4 + 6 + 2 = 12.<\/p>\n<p>Question 10.<br \/>\n5 + 9 + 1 = ________<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28836 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-44-1.bmp\" alt=\"\" width=\"239\" height=\"152\" \/><\/p>\n<p>Add 9,1 first to make 10 then add 5, sum = 5 + 9 + 1 = 15<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 5 + 9 = 14,<br \/>\nwhich is not equal to 10, now we add 9 + 1 = 10\u00a0 which is equal to 10 ,<br \/>\nand now we add 5 + 1 = 6 which is not equal to 10,<br \/>\nSo to make 10 we add 9,1 first then add 5,<br \/>\nSo the sum is 5 + 9 + 1 = 15.<\/p>\n<p>Question 11.<br \/>\n<strong>DIG DEEPER!<\/strong><br \/>\nWhat do you know about the missing addends and the sum?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24555\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-74.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 74\" width=\"141\" height=\"171\" \/><br \/>\nAnswer:<br \/>\nWe know the sum of the missing addends is 10 and the total sum is 10 + 3 = 13.<\/p>\n<p>Explanation:<br \/>\nFrom the picture it is showing that if we add the missing<br \/>\naddends we get sum as 10 and the total sum is 10 + 3 = 13.<br \/>\nSo whenever we are adding two missing addends we should always check,<br \/>\ntheir sum should be always 10, Example if one number is 1<br \/>\nother numbers will be 10-1 = 9. So the missing numbers are (1,9).<br \/>\nIt can be even (2,8), (3,7),(4,6),(5,5),(6,4),(7,3),(8,2) or (9,1).<\/p>\n<p><strong>Think and Grow: Modeling Real Life<\/strong><\/p>\n<p>You need to knock down 20 pins to win. Do you win?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24554\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-75.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 75\" width=\"140\" height=\"208\" \/><br \/>\nEquation:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24553\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-76.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 76\" width=\"265\" height=\"73\" \/><br \/>\nShow how you know:<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28840 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-45.bmp\" alt=\"\" width=\"265\" height=\"132\" \/><br \/>\n6 + 3 + 7 = 16, No we will not win.<\/p>\n<p>Explanation:<br \/>\nGiven pins as 6,3,7 if we add all we get 6 + 3 + 7 = 16,<br \/>\nwe need 20 pins to knock down to win and we got 16 which are less than 20,<br \/>\nSo no we will not win.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 12.<br \/>\nYour hockey team needs 12 goals to break a record. Does your team break the record?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24552\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-77.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 77\" width=\"78\" height=\"111\" \/><br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24551\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-78.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 78\" width=\"131\" height=\"132\" \/><br \/>\nEquation:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24550\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-79.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 79\" width=\"262\" height=\"77\" \/><br \/>\nShow how you know:<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28846 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-46.bmp\" alt=\"\" width=\"262\" height=\"132\" \/><br \/>\n5 + 6 + 4 = 15, Yes my hockey team will break the record.<\/p>\n<p>Explanation:<br \/>\nGiven the goals made are 5,6,4 so the total number of goals<br \/>\nmade are 5 + 6 + 4 = 15, to break hockey record<br \/>\nwe need 12 goals as my team made 15 goals which is more than 12,<br \/>\nYes my hockey team will break the record.<\/p>\n<h3><a id=\"Add_Three_Numbers_by_Making_a_10_Practice_4.5\"><\/a>Add Three Numbers by Making a 10 Practice 4.5<\/h3>\n<p>Make a 10 to add.<\/p>\n<p>Question 1.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24549\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-80.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 80\" width=\"163\" height=\"103\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28850 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-47.bmp\" alt=\"\" width=\"163\" height=\"132\" \/><\/p>\n<p>Add 6,4 first to make 10 then add 8, sum = 6 + 8 + 4 = 18<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 6 + 8 = 14,<br \/>\nwhich is not equal to 10, now we add 8 + 4 = 12<br \/>\nwhich is not equal to 10 ,<br \/>\nand now we add 6 + 4 = 10 which is equal to 10,<br \/>\nSo to make 10 we add 6,4 first then add 8,<br \/>\nSo the sum is 6 + 8 + 4 = 18.<\/p>\n<p>Question 2.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24548\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-81.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 81\" width=\"130\" height=\"127\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28851 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-48.bmp\" alt=\"\" width=\"147\" height=\"132\" \/><\/p>\n<p>Add 3,7 first to make 10 then add 4, sum = 3 + 7 + 4 = 14<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 3 + 7 = 10,<br \/>\nwhich is equal to 10, now we add 7 + 4 = 11<br \/>\nwhich is not equal to 10 ,<br \/>\nand now we add 3 + 4 = 7 which is not equal to 10,<br \/>\nSo to make 10 we add 3,7 first then add 4,<br \/>\nSo the sum is 3 + 7 + 4 = 14.<\/p>\n<p>Question 3.<br \/>\n5 + 8 + 2 = _______<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28852 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-49.bmp\" alt=\"\" width=\"239\" height=\"152\" \/><\/p>\n<p>Add 8,2 first to make 10 then add 5, sum = 5 + 8 + 2 = 15<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 5 + 8 = 13,<br \/>\nwhich is not equal to 10, now we add 8 + 2 = 10<br \/>\nwhich is equal to 10 ,<br \/>\nand now we add 5 + 2 = 7 which is not equal to 10,<br \/>\nSo to make 10 we add 8,2 first then add 5,<br \/>\nSo the sum is 5 + 8 + 2 = 15.<\/p>\n<p>Question 4.<br \/>\n1 + 9 + 7 = _________<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28854 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-50.bmp\" alt=\"\" width=\"239\" height=\"152\" \/><\/p>\n<p>Add 1,9 first to make 10 then add 7, sum = 1 + 9 + 7 = 17<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 1 + 9 = 10,<br \/>\nwhich is equal to 10, now we add 9 + 7 = 16<br \/>\nwhich is not equal to 10 ,<br \/>\nand now we add 1 + 7 = 8 which is not equal to 10,<br \/>\nSo to make 10 we add 1,9 first then add 7,<br \/>\nSo the sum is 1 + 9 + 7 = 17.<\/p>\n<p>Question 5.<br \/>\n<strong>DIG DEEPER!<\/strong><br \/>\nWhat do you know about the missing addends and the sum?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24547\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-82.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 82\" width=\"145\" height=\"181\" \/><br \/>\nAnswer:<br \/>\nwe know the sum of the missing addends is 10 and the total sum is 10 + 2 = 12.<\/p>\n<p>Explanation:<br \/>\nFrom the picture it is showing that if we add the missing<br \/>\naddends we get sum as 10 and the total sum is 10 + 2 = 12.<br \/>\nSo whenever we are adding two missing addends we should always check,<br \/>\ntheir sum should be always 10, Example if one number is 2<br \/>\nother number will be 10-2 = 8. So the missing addends here are (2,8).<br \/>\nIt can be (1,9),(3,7),(4,6),(5,5),(6,4),(7,3),(8,2) or (9,1).<\/p>\n<p>Question 6.<br \/>\n<strong>Modeling Real Life<\/strong><br \/>\nYour baseball team needs 15 runs to break a record. Does your team break the record?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24546\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-83.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 83\" width=\"69\" height=\"113\" \/><br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24545\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-84.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 84\" width=\"94\" height=\"106\" \/><br \/>\nEquation:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24544\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-85.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 85\" width=\"261\" height=\"72\" \/><br \/>\nShow how you know:<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28859 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-51-1.bmp\" alt=\"\" width=\"261\" height=\"132\" \/><br \/>\n6 + 4 + 6 = 16, Yes my team will break the record.<\/p>\n<p>Explanation:<br \/>\nGiven my team makes 6,4,6 runs so total runs made are<br \/>\n6 + 4 + 6 = 16, to break the record we require 15 runs<br \/>\nbut the team made 16 as 16 is more than 15,<br \/>\nYes, my team will break the record.<\/p>\n<p><strong>Review &amp; Refresh<\/strong><\/p>\n<p>Circle the heavier object.<\/p>\n<p>Question 7.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24543\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-86.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 86\" width=\"188\" height=\"61\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28867 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-52.bmp\" alt=\"\" width=\"188\" height=\"132\" \/><br \/>\nExplanation:<br \/>\nBy looking at the pictures book is heavier than a pencil.<br \/>\nSo the book is circled.<\/p>\n<p>Question 8.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24542\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answer-Key-Grade-1-Chapter-4-Add-Numbers-within-20-87.png\" alt=\"Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 87\" width=\"142\" height=\"71\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28869 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-53.bmp\" alt=\"\" width=\"166\" height=\"131\" \/><br \/>\nExplanation:<br \/>\nBy looking at the pictures apple is heavier than the feather,<br \/>\nSo apple is circled.<\/p>\n<h3><a id=\"Lesson_4.6_Add_9\"><\/a>Lesson 4.6 Add 9<\/h3>\n<p><strong>Explore and Grow<\/strong><\/p>\n<p>Use counters and the ten frames to find the sum. Show how you can make a lo to solve.<\/p>\n<p><img loading=\"lazy\" class=\"alignnone size-full wp-image-24580\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-88.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 88\" width=\"453\" height=\"478\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-88.png 453w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-88-284x300.png 284w\" sizes=\"(max-width: 453px) 100vw, 453px\" \/><br \/>\nAnswer:<br \/>\n9 + 1 + 4 = 14<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28889 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-54.bmp\" alt=\"\" width=\"852\" height=\"540\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-54.bmp 852w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-54-300x190.jpg 300w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-54-768x487.jpg 768w\" sizes=\"(max-width: 852px) 100vw, 852px\" \/><br \/>\nExplanation:<br \/>\nFirst we make sum 10 , For 9 to make 10 we need 10-9=1,<br \/>\nas we have add 1 to 9 now we will minus 1 from 5 we get 5 &#8211; 1 = 4,<br \/>\nNow we write the total sum as 9 + 1 + 4 = 14 .<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Make a 10 to add.<\/p>\n<p>Question 1.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24579\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-89.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 89\" width=\"493\" height=\"167\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-89.png 493w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-89-300x102.png 300w\" sizes=\"(max-width: 493px) 100vw, 493px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-28932 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-55.bmp\" alt=\"\" width=\"509\" height=\"177\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-55.bmp 509w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-55-300x104.jpg 300w\" sizes=\"(max-width: 509px) 100vw, 509px\" \/><br \/>\nSum is 9 + 1 + 2 = 12\u00a0 or\u00a0 9 + 3 = 12.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10 , For 9 to make 10 we need 10-9=1,<br \/>\nas we have to\u00a0 add 1 to 9 now\u00a0 we will minus 1 from 3 we get 3 &#8211; 1 = 2,<br \/>\nNow we write the total sum as 9 + 1 + 2 = 12\u00a0 or 9 + 3 = 12.<\/p>\n<p>Question 2.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24578\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-90.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 90\" width=\"493\" height=\"163\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-90.png 493w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-90-300x99.png 300w\" sizes=\"(max-width: 493px) 100vw, 493px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29007 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-56.bmp\" alt=\"\" width=\"509\" height=\"177\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-56.bmp 509w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-56-300x104.jpg 300w\" sizes=\"(max-width: 509px) 100vw, 509px\" \/><br \/>\nSum is 9 + 1 + 5 = 15 or 9 + 6 = 15.<br \/>\nExplanation:<br \/>\nFirst we make sum 10 , For 9 to make 10 we need 10-9=1,<br \/>\nas we have to\u00a0 add 1 to 9 now\u00a0 we will minus 1 from 6 we get 6 &#8211; 1 = 5,<br \/>\nNow we write the total sum as 9 + 1 + 5 = 15 or 9 + 6 = 15.<\/p>\n<p><strong>Apply and Grow: Practice<\/strong><\/p>\n<p>Make a 10 to add.<\/p>\n<p>Question 3.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24577\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-91.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 91\" width=\"475\" height=\"169\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-91.png 475w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-91-300x107.png 300w\" sizes=\"(max-width: 475px) 100vw, 475px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29010 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-57.bmp\" alt=\"\" width=\"509\" height=\"177\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-57.bmp 509w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-57-300x104.jpg 300w\" sizes=\"(max-width: 509px) 100vw, 509px\" \/><br \/>\nSum is 9 + 1 + 1 = 11\u00a0 or 9 + 2 = 11.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10 , For 9 to make 10 we need 10-9=1,<br \/>\nas we have to\u00a0 add 1 to 9 now\u00a0 we will minus 1 from 2 we get 2 &#8211; 1 = 1,<br \/>\nNow we write the total sum as 9 + 1 + 1 = 11\u00a0 or 9 + 2 = 11.<\/p>\n<p>Question 4.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24576\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-92.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 92\" width=\"183\" height=\"201\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29011 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-58.bmp\" alt=\"\" width=\"208\" height=\"209\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-58.bmp 208w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-58-150x150.jpg 150w\" sizes=\"(max-width: 208px) 100vw, 208px\" \/><br \/>\nSum is 9 + 1 + 8 = 18\u00a0 or 9 + 9 = 18.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10 , For 9 to make 10 we need 10-9=1,<br \/>\nas we have to add 1 to 9 now\u00a0 we will minus 1 from 9 we get 9 &#8211; 1 = 8,<br \/>\nNow we write the total sum as 9 + 1 + 8 = 18\u00a0 or 9 + 9 = 18.<\/p>\n<p>Question 5.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24575\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-93.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 93\" width=\"179\" height=\"200\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29014 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-59.bmp\" alt=\"\" width=\"208\" height=\"209\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-59.bmp 208w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-59-150x150.jpg 150w\" sizes=\"(max-width: 208px) 100vw, 208px\" \/><br \/>\nSum is 9 + 1 + 4 = 14 or 9 + 5 = 14.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10 , For 9 to make 10 we need 10-9=1,<br \/>\nas we have to add 1 to 9 now\u00a0 we will minus 1 from 5 we get 5 &#8211; 1 = 4,<br \/>\nNow we write the total sum as 9 + 1 + 4 = 14 or 9 + 5 = 14.<\/p>\n<p>Question 6.<br \/>\n<strong>DIG DEEPER!<\/strong><br \/>\nUse the ten frame to complete the equations.<br \/>\n9 + ? = 17<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24574\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-94.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 94\" width=\"123\" height=\"115\" \/><br \/>\n10 + _______ = 17<br \/>\nSo, 9 + ________ = 17<br \/>\nAnswer:<br \/>\n10 + 7 = 17,<br \/>\nSo\u00a0 9 + 1 + 7 = 17<\/p>\n<p>Explanation:<br \/>\nGiven 10 + ____ = 17, to find the missing number we take it as X,<br \/>\n10 + X = 17 , X = 17 &#8211; 10 =7. So the equation is 10 + 7 = 17.<br \/>\nNow we write 10 as 9 + 1 by using ten frame and<br \/>\nadd 7 so the total sum is 9 + 1 + 7 = 17 or 10 + 7 = 17.<\/p>\n<p><strong>Think and Grow: Modeling Real Life<\/strong><\/p>\n<p>You have 9 stickers and earn 5 more. Your friend has 6 stickers and earns 10 more. Do you and your friend have the same number of stickers?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24573\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-95.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 95\" width=\"118\" height=\"93\" \/><br \/>\nAddition equations:<br \/>\n<span style=\"text-decoration: underline;\">you<\/span>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 <span style=\"text-decoration: underline;\">Friend<br \/>\n<\/span>9 + 5 = 14\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 6 + 10 = 16<\/p>\n<p>Yes\u00a0 \u00a0 \u00a0 <span style=\"text-decoration: underline;\">\u00a0No<\/span><\/p>\n<p>Show how you know:<br \/>\nAnswer:<br \/>\nMy equation is 9 + 5 = 14 and friend has 6 + 10 =16<br \/>\nas 14 is not equal to 16, so I and my friend don&#8217;t<br \/>\nhave the same number of stickers.<\/p>\n<p>Explanation:<br \/>\nGiven I have 9 stickers and earn 5 more means in total I have 9 + 5 = 14 stickers and friend has 6 stickers and earns 10 more means in total friend have 6 + 10 = 16 stickers,<br \/>\nNow comparing between me and my friend as 14 and 16 are not same, So No, I and my friend do not have the same number of stickers.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 7.<br \/>\nYour friend has 9 magnets and finds 6 more. You have 5 magnets and find 10 more. Do you and your friend have the same number of magnets?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24572\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-96.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 96\" width=\"108\" height=\"131\" \/><br \/>\nAddition equations:<br \/>\n<span style=\"text-decoration: underline;\">\u00a0you<\/span>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0<span style=\"text-decoration: underline;\">Friend<\/span><br \/>\n5 + 10 =15\u00a0 \u00a0 \u00a0 9 + 6 = 15<\/p>\n<p><span style=\"text-decoration: underline;\">Yes\u00a0<\/span> \u00a0 \u00a0 \u00a0No<\/p>\n<p>Show how you know:<\/p>\n<p>Answer:<br \/>\nMy equation is 5 + 10 = 15 and friend equation is 9 + 6 = 15,<br \/>\nas both are equal, So Yes, I and my friend have the same number of magnets.<\/p>\n<p>Explanation:<br \/>\nGiven I have 5 magnets and find 10 more means in total, I have 5 + 10 = 15 magnets and friend has 9 magnets and finds 6 more means in total friend have 9 + 6 = 15 magnets, Now comparing between me and my friend as 15 and 15 are same, So Yes, I and my friend have the same number of magnets.<\/p>\n<h3><a id=\"Add_9_Practice_4.6\"><\/a>Add 9 Practice 4.6<\/h3>\n<p>Make a 10 to add<\/p>\n<p>Question 1.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24571\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-97.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 97\" width=\"488\" height=\"166\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-97.png 488w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-97-300x102.png 300w\" sizes=\"(max-width: 488px) 100vw, 488px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29034 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-60.bmp\" alt=\"\" width=\"488\" height=\"209\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-60.bmp 488w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-60-300x128.jpg 300w\" sizes=\"(max-width: 488px) 100vw, 488px\" \/><br \/>\nSum is 9 + 1 + 2 = 12 or 9 + 3 = 12.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10, For 9 to make 10 we need 10-9=1,<br \/>\nas we have to add 1 to 9 now we will minus 1 from 3 we get 3 &#8211; 1 = 2,<br \/>\nNow we write the total sum as 9 + 1 + 2 = 12 or 9 + 3 = 12.<\/p>\n<p>Question 2.<br \/>\n<strong>DIG DEEPER!<\/strong><br \/>\nUse the ten frame to complete the equations.<br \/>\n16 = ? + ?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24570\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-98.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 98\" width=\"124\" height=\"113\" \/><br \/>\n10 + ___6_____ = ___16____<br \/>\nSo, 16 = __9 +__1____ + __6___.<br \/>\nAnswer:<br \/>\nWe write the equation as 16 = 10 + 6<br \/>\nSo 16 =\u00a0 9 + 1 + 6 or 16 = 10 + 6<\/p>\n<p>Explanation:<br \/>\nGiven 10 + ____ = 16, to find the missing number we take it as X,<br \/>\n10 + X = 16 , X = 16 &#8211; 10 =6. So the equation is 10 + 6 = 16.<br \/>\nNow we write 10 as 9 + 1 by using the ten frame<br \/>\nand add 6 so the total sum is 9 + 1 + 6 = 16 or 10 + 6 = 16.<\/p>\n<p>Question 3.<br \/>\n<strong>Modeling Real Life<\/strong><br \/>\nYou have 9 rocks and collect 7 more. Your friend has 8 rocks and collects 8 more. Do you and your friend have the same number of rocks?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24569\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-99.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 99\" width=\"98\" height=\"108\" \/><br \/>\n<span style=\"text-decoration: underline;\">Yes\u00a0<\/span> \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0No<br \/>\nShow how you know:<br \/>\nAnswer:<br \/>\nI have 9 + 7 = 16 rocks,<br \/>\nFriend have 8 + 8 = 16 rocks,<br \/>\nYes, I and my friend have the same number of rocks.<\/p>\n<p>Explanation:<br \/>\nGiven I have 9 rocks and collected 7 more,<br \/>\nSo I have total 9 + 7 = 16 rocks and my friend have 8 rocks and collects 8 rocks total he have 16 rocks,<br \/>\nNow comparing both me and my friend both have the equal number of rocks, Yes, I and my friend have the same number of rocks.<\/p>\n<p><strong>Review &amp; Refresh<\/strong><\/p>\n<p>Circle the longer object.<\/p>\n<p>Question 4.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24568\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-100.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 100\" width=\"177\" height=\"134\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29043 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-61.bmp\" alt=\"\" width=\"208\" height=\"209\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-61.bmp 208w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-61-150x150.jpg 150w\" sizes=\"(max-width: 208px) 100vw, 208px\" \/><br \/>\nExplanation:<br \/>\nBy seeing the picture we can identify yellow spectacles are longer than the red spectacles, So circled the yellow spectacles.<\/p>\n<p>Question 5.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24567\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-1st-Grade-1-Chapter-4-Add-Numbers-within-20-101.png\" alt=\"Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 101\" width=\"213\" height=\"122\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29046 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Gr-1-Image-62.bmp\" alt=\"\" width=\"286\" height=\"243\" \/><br \/>\nExplanation:<br \/>\nBy seeing the picture we can identify tooth paste is longer than the toothbrush, So circled the toothpaste.<\/p>\n<h3><a id=\"Lesson_4.7_Make_a_10_ Add\"><\/a>Lesson 4.7 Make a 10 to Add<\/h3>\n<p><strong>Explore and Grow<\/strong><\/p>\n<p>Use counters and the ten frame to find the sum.<br \/>\nShow how you can make a lo to solve.<\/p>\n<p><img loading=\"lazy\" class=\"alignnone wp-image-24595\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-102.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 102\" width=\"362\" height=\"384\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-102.png 451w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-102-283x300.png 283w\" sizes=\"(max-width: 362px) 100vw, 362px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29418 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-22.bmp\" alt=\"\" width=\"681\" height=\"394\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-22.bmp 681w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-22-300x174.jpg 300w\" sizes=\"(max-width: 681px) 100vw, 681px\" \/><\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10, For 8 to make 10 we need 10-8=2,<br \/>\nas we have to add 2 to 8 now we will minus 2 from 6 we get 6 &#8211; 2 = 4,<br \/>\nNow we write the total sum as 8 + 2 + 4 = 14.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Make a 10 to add.<\/p>\n<p>Question 1.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24594\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-103.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 103\" width=\"492\" height=\"165\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-103.png 492w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-103-300x101.png 300w\" sizes=\"(max-width: 492px) 100vw, 492px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29419 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-23.bmp\" alt=\"\" width=\"583\" height=\"188\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-23.bmp 583w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-23-300x97.jpg 300w\" sizes=\"(max-width: 583px) 100vw, 583px\" \/><br \/>\nSum as 8 + 2 + 3 = 13 or 8 + 5 = 13.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10, For 8 to make 10 we need 10-8=2,<br \/>\nas we have to add 2 to 8 now we will minus 2 from 5 we get 5 &#8211; 2 = 3,<br \/>\nNow we write the total sum as 8 + 2 + 3 = 13 or 8 + 5 = 13.<\/p>\n<p>Question 2.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24593\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-104.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 104\" width=\"495\" height=\"162\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-104.png 495w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-104-300x98.png 300w\" sizes=\"(max-width: 495px) 100vw, 495px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29421 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-24.bmp\" alt=\"\" width=\"510\" height=\"194\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-24.bmp 510w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-24-300x114.jpg 300w\" sizes=\"(max-width: 510px) 100vw, 510px\" \/><br \/>\nSum as 7 + 3 + 4\u00a0 = 14 or 7 + 7 = 14.<\/p>\n<p>Explanation:<br \/>\nFirst, we make sum 10, For 7 to make 10 we need 10-7=3,<br \/>\nas we have to add 3 to 7 now we will minus 3 from 7 we get 7 &#8211; 3 = 4,<br \/>\nNow we write the total sum as 7 + 3 + 4\u00a0 = 14 or 7 + 7 = 14.<\/p>\n<p><strong>Apply and Grow: Practice<\/strong><\/p>\n<p>Make a 10 to add.<\/p>\n<p>Question 3.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24592\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-105.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 105\" width=\"491\" height=\"166\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-105.png 491w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-105-300x101.png 300w\" sizes=\"(max-width: 491px) 100vw, 491px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29422 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-25.bmp\" alt=\"\" width=\"510\" height=\"194\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-25.bmp 510w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-25-300x114.jpg 300w\" sizes=\"(max-width: 510px) 100vw, 510px\" \/><br \/>\nSum as 7 + 3 + 3\u00a0 = 13 or 7 + 6 = 13.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10, For 7 to make 10 we need 10-7=3,<br \/>\nas we have to add 3 to 7 now we will minus 3 from 6 we get 6 &#8211; 3 = 3,<br \/>\nNow we write the total sum as 7 + 3 + 3\u00a0 = 13 or 7 + 6 = 13.<\/p>\n<p>Question 4.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24591\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-106.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 106\" width=\"496\" height=\"164\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-106.png 496w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-106-300x99.png 300w\" sizes=\"(max-width: 496px) 100vw, 496px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29436 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-26.bmp\" alt=\"\" width=\"510\" height=\"194\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-26.bmp 510w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-26-300x114.jpg 300w\" sizes=\"(max-width: 510px) 100vw, 510px\" \/><br \/>\nSum as 7 + 3 + 1\u00a0 = 11 or 7 + 4 = 11.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10, For 7 to make 10 we need 10-7=3,<br \/>\nas we have to add 3 to 7 now we will minus 3 from 4 we get 4 &#8211; 3 = 1,<br \/>\nNow we write the total sum as 7 + 3 + 1\u00a0 = 11 or 7 + 4 = 11.<\/p>\n<p>Question 5.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24590\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-107.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 107\" width=\"182\" height=\"166\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29437 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-27.bmp\" alt=\"\" width=\"204\" height=\"177\" \/><br \/>\nSum as 8 + 2 + 5 = 15 or 8 + 7 = 15.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10, For 8 to make 10 we need 10-8=2,<br \/>\nas we have to add 2 to 8 now we will minus 2 from 7 we get 7 &#8211; 2 = 5,<br \/>\nNow we write the total sum as 8 + 2 + 5 = 15 or 8 + 7 = 15.<\/p>\n<p>Question 6.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24589\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-108.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 108\" width=\"181\" height=\"165\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29442 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-28.bmp\" alt=\"\" width=\"204\" height=\"177\" \/><br \/>\nSum as 6 + 4 + 2 = 12 or 6 + 6 = 12.<br \/>\nExplanation:<br \/>\nFirst we make sum 10, For 8 to make 10 we need 10-6=4,<br \/>\nas we have to add 4 to 6 now we will minus 4 from 6 we get 6 &#8211; 4 = 2,<br \/>\nNow we write the total sum as 6 + 4 + 2 = 12 or 6 + 6 = 12.<\/p>\n<p>Question 7.<br \/>\n<strong>MP Number Sense<\/strong><br \/>\nUse 4, 7, and 10 to complete the sentence.<br \/>\n7 + ___7_____ has the same sum as ___4___ + __10_____.<br \/>\nAnswer:<br \/>\n7 + 7\u00a0 has the same sum as\u00a0 4 + 10<\/p>\n<p>Explanation:<br \/>\nGiven to use numbers 4,7,10 to make the sentence<br \/>\n7 +\u00a0 _____ = ________ + _______ both sides sum is same<br \/>\nAs left side 7 is given we substitute and check first we use 4, then 7 and 10<br \/>\n7 +\u00a0 4 = 11 now we have numbers 7 and 10, sum is 7+10 = 17<br \/>\nSo (7 + 4)= 11\u00a0 \u2260 (7 + 10) =17, next we take 7 and check 7 + 7 = 14<br \/>\nnow we have numbers 4 , 10 and sum is 4 + 10 = 14<br \/>\nSo (7 + 7) = 14 = (4 + 10) = 14 here if we take for 7 left side and 4,10 right<br \/>\nwe get same sum both side, now we\u00a0 even check taking 10 first,<br \/>\n7 + 10 = 17 in left side and we have numbers 7 and 4 for right as 7 + 4 =11,<br \/>\nSo (7 + 10)= 17 \u2260 (7 + 4) =11, So to make both the same sum<br \/>\nwe take left side number as 7 and right side numbers 4, 10<br \/>\nmaking the sentence as (7 + 7) = (4 + 10) = 14.<\/p>\n<p><strong>Think and Grow: Modeling Real Life<\/strong><\/p>\n<p>There are 8 crabs. 7 more join them. There are 10 turtles. 5 more join them.<br \/>\nIs the number of crabs the same as the number of turtles?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24588\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-109.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 109\" width=\"132\" height=\"54\" \/><br \/>\nAddition equations:<br \/>\nYes\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 No<br \/>\nShow how you know:<br \/>\nAnswer:<br \/>\nAddition equations:<br \/>\nCrabs\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0Turtles<br \/>\n8 + 7 = 15\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 10 + 5 =15<br \/>\nYes, the number of crabs are the same as the number of turtles.<\/p>\n<p>Explanation:<br \/>\nGiven 8 crabs and 7 more joined them so the number of crabs are 8 + 7 = 15 crabs and there are 10 turtles and 5 more joined them<br \/>\nSo the total number of turtles are 10 + 5 = 15 turtles, as both are 15,<br \/>\nYes, the number of crabs are the same as the number of turtles.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 8.<br \/>\nThere are 6 squirrels. 6 more join them. There are 10 birds. 2 more join them. Is the number of squirrels the same as the number of birds?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24587\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-110.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 110\" width=\"121\" height=\"77\" \/><br \/>\nAddition equations:<br \/>\nYes\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0No<br \/>\nShow how you know:<br \/>\nAnswer:<br \/>\nSquirrels\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Birds<br \/>\n6 + 6 = 12\u00a0 \u00a0 10 + 2 = 12<br \/>\nYes, the number of squirrels are the same as the number of birds.<\/p>\n<p>Explanation:<br \/>\nGiven 6 squirrels and 6 more joined them so total squirrels are 6 + 6 = 12 and 10 birds, 2 more birds joined making total as 10 + 2 = 12 birds as both are 12,<br \/>\nYes, the number of squirrels are the same as the number of birds.<\/p>\n<h3><a id=\"Make_a_10_ Add_Practice_4.7\"><\/a>Make a 10 to Add Practice 4.7<\/h3>\n<p>Make a 10 to add.<\/p>\n<p>Question 1.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24586\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-111.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 111\" width=\"476\" height=\"169\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-111.png 476w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-111-300x107.png 300w\" sizes=\"(max-width: 476px) 100vw, 476px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29520 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-29.bmp\" alt=\"\" width=\"476\" height=\"177\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-29.bmp 476w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-29-300x112.jpg 300w\" sizes=\"(max-width: 476px) 100vw, 476px\" \/><br \/>\nSum as 6 + 4 + 1\u00a0 = 11 or 6 + 5 = 11.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10, For 6 to make 10 we need 10-6=4,<br \/>\nas we have to add 4 to 6 now we will minus 4 from 5 we get 5 &#8211; 4 = 1,<br \/>\nNow we write the total sum as 6 + 4 + 1\u00a0 = 11 or 6 + 5 = 11.<\/p>\n<p>Question 2.<br \/>\n<strong>MP Number Sense<\/strong><br \/>\nUse 2, 6, and 10 to complete the sentence.<br \/>\n________ + ________ has the same sum as ______ + 6.<br \/>\nAnswer:<\/p>\n<p>2 + 10\u00a0 \u00a0has the same sum as\u00a0 6 + 6<\/p>\n<p>Explanation:<br \/>\nGiven to use numbers 2,6,10 to make the sentence<br \/>\n_______ +\u00a0 _____ = ________ +\u00a0 6 both sides sum is same<br \/>\nAs right side 6 is given we substitute and check first we use 2, then 6 and 10,<br \/>\n2 +\u00a0 6 = 8 now we have numbers 6 and 10, sum is 6 + 10 = 16<br \/>\nSo (6 + 10) = 16\u00a0 \u2260 (2 + 6) = 8, next we take 6 and check 6 + 6 = 12<br \/>\nnow we have numbers 2 , 10 and sum is 2 + 10 = 12<br \/>\nSo (2 + 10) = 12 = ( 6 + 6) = 12 here if we take for 6 right side and 2,10 left<br \/>\nwe get same sum both side, now we\u00a0 even check taking 10 first,<br \/>\n10 + 6 = 16 in right side and we have numbers 2 and 6 for left as 2 + 6 =8,<br \/>\nSo (2 + 6)= 8 \u2260 (10 + 6) =16, So to make both the same sum<br \/>\nwe take left side numbers as 2,10 and right side number 6<br \/>\nmaking the sentence as (2 + 10) = (6 + 6) = 12.<\/p>\n<p>Question 3.<br \/>\n<strong>Modeling Real Life<\/strong><br \/>\nThere are 7 monkeys. 4 more join them. There are 6 birds. 5 more join them. Is the number of monkeys the same as the number of birds?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24585\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-112.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 112\" width=\"76\" height=\"96\" \/><br \/>\nYes\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 No<br \/>\nShow how you know:<br \/>\nAnswer:<br \/>\nEquations are:\u00a0 \u00a0Monkeys\u00a0 \u00a0 \u00a0 \u00a0Birds<br \/>\n7 + 4 = 11\u00a0 \u00a0 \u00a06 + 5 = 11<br \/>\nYes, the number of monkeys are the same as the number of birds.<\/p>\n<p>Explanation:<br \/>\nGiven 7 monkeys and 4 more joined them so total<br \/>\nmonkeys are 7 + 4 = 11 and 6 birds, 5 more birds joined<br \/>\nmaking total as 6 + 5 = 11 birds as both are 11,<br \/>\nYes, the number of monkeys are the same as the number of birds.<\/p>\n<p><strong>Review &amp; Refresh<\/strong><\/p>\n<p>Question 4.<br \/>\nThere are 3 <img loading=\"lazy\" class=\"alignnone size-full wp-image-24584\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-113.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 113\" width=\"41\" height=\"28\" \/><br \/>\n2 more <img loading=\"lazy\" class=\"alignnone size-full wp-image-24584\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-113.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 113\" width=\"41\" height=\"28\" \/> join them.<br \/>\nHow many <img loading=\"lazy\" class=\"alignnone size-full wp-image-24584\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-113.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 113\" width=\"41\" height=\"28\" \/> are there now?<br \/>\n____3____ + ___2____ = ____5____ <img loading=\"lazy\" class=\"alignnone size-full wp-image-24584\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-113.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 113\" width=\"41\" height=\"28\" \/><br \/>\nAnswer:<br \/>\n3 + 2 = 5, there are 5 aero planes now.<\/p>\n<p>Explanation:<br \/>\nGiven there are 3 aero planes and 2 more join them making total<br \/>\nas 3 + 2 = 5 , therefore there are 5 aero planes now.<\/p>\n<p>Question 5.<br \/>\nThere are 4 <img loading=\"lazy\" class=\"alignnone size-full wp-image-24583\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-114.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 114\" width=\"41\" height=\"25\" \/><br \/>\n6 more <img loading=\"lazy\" class=\"alignnone size-full wp-image-24583\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-114.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 114\" width=\"41\" height=\"25\" \/> join them.<br \/>\nHow many <img loading=\"lazy\" class=\"alignnone size-full wp-image-24583\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-114.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 114\" width=\"41\" height=\"25\" \/> are there now?<br \/>\n___4_____ + ___6_____ = ___10_____ <img loading=\"lazy\" class=\"alignnone size-full wp-image-24583\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-114.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 114\" width=\"41\" height=\"25\" \/><br \/>\nAnswer:<br \/>\n4 + 6 = 10, there are 10 airplanes now.<\/p>\n<p>Explanation:<br \/>\nGiven there are 4 aero planes and 6 more join them making total as\u00a0 4 + 6 = 10, therefore there are 10 aero planes now.<\/p>\n<h3><a id=\"Lesson_4.8_Problem_Solving:_Addition_within_20\"><\/a>Lesson 4.8 Problem Solving: Addition within 20<\/h3>\n<p><strong>Explore and Grow<\/strong><\/p>\n<p>Newton has 9 red crayons, 3 blue crayons, and 1 yellow crayon. How many crayons does he have in all?<\/p>\n<p>________ crayons<br \/>\nAnswer:<br \/>\nNewton has 9 + 3 + 1 = 13 crayons in all.<\/p>\n<p>Explanation:<br \/>\nGiven Newton has 9 red crayons, 3 blue crayons and 1 yellow crayon,<br \/>\nSo the total number of crayons Newton has are 9 + 3 + 1 = 13 crayons,<br \/>\ntherefore Newton has 13 crayons in all.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 1.<br \/>\nYou have 6 notebooks. You buy 5 more. How many notebooks do you have now?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24608\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-115.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 115\" width=\"99\" height=\"85\" \/><br \/>\nCircle what you know.<br \/>\nUnderline what you need to find.<br \/>\nSolve:<\/p>\n<p>_______ \u25cb _______ = _______\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0_______ notebooks<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-medium wp-image-29557\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-30-300x112.jpg\" alt=\"\" width=\"300\" height=\"112\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-30-300x112.jpg 300w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-30.bmp 382w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/>notebooks<br \/>\nI have <span style=\"text-decoration: underline;\">11<\/span> notebooks in all.<\/p>\n<p>Explanation:<br \/>\nGiven I have 6 note books and buy 5 more , So I know<br \/>\nI have 6 &amp; 5 books, So I circled what I know, I need to find<br \/>\nhow many total notebooks I do have now, so I underlined it,<br \/>\nmaking 6 + 5 = 11 notebooks. So I have\u00a0 total 11 notebooks now.<\/p>\n<p><strong>Apply and Grow: Practice<\/strong><\/p>\n<p>Question 2.<br \/>\nThere are 6 soccer balls, 10 basketballs, and 4 volleyballs. How many balls are there in all?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24607\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-116.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 116\" width=\"109\" height=\"67\" \/><br \/>\nCircle what you know.<br \/>\nUnderline what you need to find.<br \/>\nSolve:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24606\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-117.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 117\" width=\"425\" height=\"103\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-117.png 425w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-117-300x73.png 300w\" sizes=\"(max-width: 425px) 100vw, 425px\" \/><br \/>\nAnswer:<br \/>\n<a href=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-31.bmp\"><img loading=\"lazy\" class=\"alignnone wp-image-29562 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-31.bmp\" alt=\"\" width=\"382\" height=\"143\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-31.bmp 382w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-31-300x112.jpg 300w\" sizes=\"(max-width: 382px) 100vw, 382px\" \/> <\/a>balls<br \/>\nI have <span style=\"text-decoration: underline;\">20<\/span> balls in all.<\/p>\n<p>Explanation:<br \/>\nGiven there are\u00a0 6 soccer balls, 10 basketballs, and 4 volleyballs, So I know 6 , 10 &amp; 4 balls, So I circled what I know, I need to find<br \/>\nhow many total balls there in all so I underlined it, making 6 + 10 + 4 = 20 balls, therefore there are total 20 balls in all.<\/p>\n<p>Question 3.<br \/>\nYou do 8 push-ups. Your friend does I fewer than you. How many push-ups do you and your friend do in all?<\/p>\n<p>____15_____ push-ups<br \/>\nAnswer:<br \/>\nIn total, I and my friend does 15 push-ups in all.<\/p>\n<p>Explanation:<br \/>\nGiven I do 8 push-ups and friend does 1 fewer than me<br \/>\nmeans 8-1 = 7 push-ups now total number of push-ups are<br \/>\n8 + 7 = 15, So in total I and my friend does 15 push-ups in all.<\/p>\n<p>Question 4.<br \/>\n<strong>YOU BE THE TEACHER<\/strong><br \/>\nNewton has 9 magnets. Descartes has 8 more than Newton. Your friend uses a bar model to show how many magnets Descartes has. Is your friend correct? Show how you know.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24605\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-118.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 118\" width=\"279\" height=\"153\" \/><img loading=\"lazy\" class=\"alignnone size-full wp-image-24605\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-118.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 118\" width=\"279\" height=\"153\" \/><br \/>\nAnswer:<br \/>\nNo, your friend is not correct as in bar model it is showing Descartes has 8 magnets.<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29572 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-32.bmp\" alt=\"\" width=\"480\" height=\"143\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-32.bmp 480w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-32-300x89.jpg 300w\" sizes=\"(max-width: 480px) 100vw, 480px\" \/><br \/>\nDescartes has 9 + 8 =\u00a0 17 magnets.<br \/>\nExplanation :<br \/>\nGiven Newton has 9 magnets and Descartes has 8 more than Newton means Descartes has 9 + 8 = 17 magnets. But the bar model is showing Descartes has only 8 magnets, I have shown in the figure Descartes have 9 + 8 = 17 Magnets.<\/p>\n<p><strong>Think and Grow: Modeling Real Life<\/strong><\/p>\n<p>You have 5 bracelets. You have 7 fewer than your friend. How many bracelets does your friend have?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24604\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-119.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 119\" width=\"119\" height=\"80\" \/><br \/>\nCircle what you know.<br \/>\nUnderline what you need to find.<br \/>\nSolve:<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24603\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-120.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 120\" width=\"250\" height=\"90\" \/><\/p>\n<p>________ + ________ = _________\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0____12____ bracelets<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29582 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-33.bmp\" alt=\"\" width=\"481\" height=\"143\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-33.bmp 481w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-33-300x89.jpg 300w\" sizes=\"(max-width: 481px) 100vw, 481px\" \/><br \/>\nFriend have <span style=\"text-decoration: underline;\">12<\/span> bracelets.<\/p>\n<p>Explanation:<br \/>\nGiven I have 5 bracelets, I have 7 fewer than my friend means<br \/>\nfriend have in total as 5 + 7 = 12 bracelets, So circled what I know<br \/>\n5, 7 and underlined the number how many bracelets does friend have,<br \/>\nSo friend have <span style=\"text-decoration: underline;\">12<\/span> bracelets.<\/p>\n<p><strong>Show and Grow<\/strong><\/p>\n<p>Question 5.<br \/>\nYour friend finds 9 seashells. You find 6 more than your friend. How many seashells do you find?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24602\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-121.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 121\" width=\"86\" height=\"76\" \/><br \/>\nCircle what you know.<br \/>\nUnderline what you need to find.<br \/>\nSolve:<\/p>\n<p>____6_____ + ___9____ = __15_____\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 ___15_____ seashells<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29602 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-34.bmp\" alt=\"\" width=\"382\" height=\"143\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-34.bmp 382w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-34-300x112.jpg 300w\" sizes=\"(max-width: 382px) 100vw, 382px\" \/><br \/>\nI found 15 seashells.<\/p>\n<p>Explanation:<br \/>\nGiven friend finds 9 seashells and I found 6 more than my friend,<br \/>\nSo the total number of shells I found are 9 + 6 = 15 seashells.<br \/>\nI Know friend has 9 and I have more 6 seashells,<br \/>\nSo I circled it and underlined to find how many seashells I found.<\/p>\n<h3><a id=\"Problem_Solving:_Addition_within_20_Practice_4.8\"><\/a>Problem Solving: Addition within 20 Practice 4.8<\/h3>\n<p>Question 1.<br \/>\nYou have 5 robots. Your friend gives you more. Now you have 14. How many robots did your friend give you?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24601\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-122.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 122\" width=\"45\" height=\"64\" \/><br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24600\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-123.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 123\" width=\"506\" height=\"167\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-123.png 506w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-123-300x99.png 300w\" sizes=\"(max-width: 506px) 100vw, 506px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29606 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-35.bmp\" alt=\"\" width=\"382\" height=\"143\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-35.bmp 382w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-35-300x112.jpg 300w\" sizes=\"(max-width: 382px) 100vw, 382px\" \/><br \/>\nFriend has 9 robots.<\/p>\n<p>Explanation :<br \/>\nGiven I have 5 robots and now I have 14 robots so I circled it,<br \/>\nI need to find how many friend gives I have underlined it.<br \/>\nLet us take friend gives X robots and we write equation as<br \/>\n5 + X = 14, therefore X = 14 &#8211; 5 = 9 means friend gave 9 robots.<\/p>\n<p>Question 2.<br \/>\nThere are some plates on a table. You add 8 more. Now there are 12. How many plates were on the table to start?<\/p>\n<p>______4____ plates<br \/>\nAnswer:<br \/>\nThere were 4 plates on the table to start.<\/p>\n<p>Explanation:<br \/>\nLet us take X as some plates on the table, I added 8 more and<br \/>\nthere are 12 now means X + 8 = 12, Therefore X = 12 &#8211; 8 = 4,<br \/>\nSo 4 plates are there on the table to start.<\/p>\n<p>Question 3.<br \/>\n<strong>YOU BE THE TEACHER<\/strong><br \/>\nNewton has 8 tickets. Descartes has 5 more than Newton. Your friend uses a number line to show how many tickets Descartes has. Is your friend correct? Show how you know.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24599\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-124.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 124\" width=\"424\" height=\"103\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-124.png 424w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-124-300x73.png 300w\" sizes=\"(max-width: 424px) 100vw, 424px\" \/><br \/>\nAnswer:<br \/>\nDescartes has 13 Tickets,<br \/>\nYes, Friend is correct.<\/p>\n<p>Explanation:<br \/>\nGiven Newton has 8 tickets and Descartes has 5 more than Newton means 8 + 5 = 13 tickets, Descartes has 13\u00a0 tickets, Now my friend is showing this on number line he is starting from 8 because Newton has 8 and moving 5 units to right as Descartes has 5 more tickets <span style=\"font-size: 16px;\">till 13<br \/>\nwhich is the same as we did sum 8 +5 = 13, So yes, friend is correct.<\/span><\/p>\n<p>Question 4.<br \/>\nModeling Real Life You have 9 medals. You have 9 fewer than your friend. How many medals does your friend have?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24598\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-125.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 125\" width=\"135\" height=\"79\" \/><br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24597\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-126.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 126\" width=\"246\" height=\"88\" \/><\/p>\n<p>____18_______ medals<br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29623 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-36.bmp\" alt=\"\" width=\"382\" height=\"143\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-36.bmp 382w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-36-300x112.jpg 300w\" sizes=\"(max-width: 382px) 100vw, 382px\" \/><br \/>\nFriend have 18 medals.<\/p>\n<p>Explanation:<br \/>\nGiven I have 9 medals and 9 fewer than friend, So friend have<br \/>\n9 + 9 what I have, So friend have 18 medals.<\/p>\n<p><strong>Review &amp; Refresh<\/strong><\/p>\n<p>Question 5.<br \/>\n4 &#8211; 3 = ________<br \/>\nAnswer:<br \/>\n4- 3 = 1<\/p>\n<p>Explanation:<br \/>\nGiven the equation as 4 &#8211; 3 = _____ means subtract 3 from 4 we get 1<br \/>\nmaking equation as 4- 3 = 1.<\/p>\n<p>Question 6.<br \/>\n5 &#8211; 2 = ________<br \/>\nAnswer:<br \/>\n5 &#8211; 2 = 3<\/p>\n<p>Explanation:<br \/>\nGiven the equation as 5 &#8211; 2 = _____ means subtract 2 from 5 we get 3<br \/>\nmaking equation as 5 &#8211; 2 = 3.<\/p>\n<p>Question 7.<br \/>\n9 &#8211; 9 = _________<br \/>\nAnswer:<br \/>\n9 &#8211; 9 = 0<\/p>\n<p>Explanation:<br \/>\nGiven the equation as 9 &#8211; 9 = _____ means subtract 9 from 9 we get 0<br \/>\nmaking equation as 9 &#8211; 9 = 0.<\/p>\n<p>Question 8.<br \/>\n7 &#8211; 0 = _________<br \/>\nAnswer:<br \/>\n7 &#8211; 0 = 7<\/p>\n<p>Explanation:<br \/>\nGiven the equation as 7 &#8211; 0 = _____ means subtract 0 from 7 we get 7<br \/>\nmaking equation as 7- 0 = 7.<\/p>\n<h3><a id=\"Add_Numbers_within_20_Performance_Task\"><\/a>Add Numbers within 20 Performance Task<\/h3>\n<p>Question 1.<br \/>\nYou track the weather for a few weeks. Each week has 7 days.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24615\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-127.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 127\" width=\"74\" height=\"62\" \/><\/p>\n<p>a. You track the weather every day for the first week. But you miss 1 day in the second week. How many days do you track the weather?<\/p>\n<p>___13_______ days<br \/>\nAnswer:<br \/>\nI have track of 13 days weather.<\/p>\n<p>Explanation:<br \/>\nGiven each week has 7 days, I have the track for every day for the first week,<br \/>\nMeans the first week = 7 days, Now in the second week I missed 1 day means<br \/>\n7 &#8211; 1 = 6 days track in the second week, So the total number of days are<br \/>\nfirst week track + second week track = 7 + 6 = 13 , total I have track of 13 days weather.<\/p>\n<p>b. You track the weather for 1 more week. How many days in all do you track the weather?<\/p>\n<p>____20______ days<br \/>\nAnswer:<br \/>\nI have track of 20 days weather in all.<\/p>\n<p>Explanation :<br \/>\nGiven that I have tracked for 1 more week, We got 13 days before<br \/>\nand now we have 1 more week means 7 days to 13 making total as<br \/>\n13 +\u00a0 7 = 20 days, So now I have track of 20 days weather in all.<\/p>\n<p>Question 2.<br \/>\nYour friend also tracks the weather. She records 9 sunny days and 5 cloudy days.<br \/>\nHow many days does your friend track the weather?<\/p>\n<p>____14______ days<br \/>\nAnswer:<br \/>\nMy friend has 14 days track record of the weather.<\/p>\n<p>Explanation:<br \/>\nGiven my friend records 9 sunny days and 5 cloudy days<br \/>\ntrack of the weather so in all my friend has track of<br \/>\n9 + 5 = 14 days. Therefore my friend has 14 days track record of the weather.<\/p>\n<p>Question 3.<br \/>\nYou record 10 rainy days in the first three weeks. Is the number of rainy days the same as the number of sunny days?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24614\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Answers-Grade-1-Chapter-4-Add-Numbers-within-20-128.png\" alt=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 128\" width=\"205\" height=\"113\" \/><br \/>\nYes\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 No<br \/>\nShow how you know:<br \/>\nAnswer:<br \/>\nNo, Number of rainy days are not the same as the number of sunny days.<\/p>\n<p>Explanation:<br \/>\nGiven I record 10 rainy days in first three weeks and number of<br \/>\nsunny days for three weeks are 4 + 3 + 4 = 11 days , now comparing<br \/>\nwith rainy days as rainy days are less to number of sunny days we say<br \/>\nNo, number of rainy days are not the same as the number of sunny days.<\/p>\n<h3><a id=\"Add_Numbers_within_20_Chapter_Practice\"><\/a>Add Numbers within 20 Chapter Practice<\/h3>\n<h3>Add Doubles from 6 to 10 Homework &amp; Practice 4.1<\/h3>\n<p>Question 1.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24638\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-129.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 129\" width=\"160\" height=\"54\" \/><br \/>\n____10______ + ____10____ = ___20______<br \/>\nAnswer:<br \/>\n10 + 10 = 20 dots<\/p>\n<p>Explanation:<br \/>\nGiven in block 1 we have 10 dots and in block 2 we have 10 dots,<br \/>\nSo in total we have 10 + 10 = 20 dots.<\/p>\n<p>Question 2.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24637\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-130.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 130\" width=\"180\" height=\"145\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29828 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-37.bmp\" alt=\"\" width=\"212\" height=\"149\" \/><\/p>\n<p>9 + 9 = 18 dots<\/p>\n<p>Explanation:<br \/>\nGiven in block 1 we have 9 dots and in block 2 we have 9 dots,<br \/>\nSo in total we have 9 + 9 = 18 dots.<\/p>\n<h3><a id=\"Use_Doubles_within_20_Homework_&amp;_Practice_4.2\"><\/a>Use Doubles within 20 Homework &amp; Practice 4.2<\/h3>\n<p>Use the doubles 6 + 6 to find each sum.<\/p>\n<p>Question 3.<br \/>\n6 + 7 = ___13_____<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24636\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-131.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 131\" width=\"99\" height=\"52\" \/><br \/>\nAnswer:<br \/>\n6 + 7\u00a0 = 13<\/p>\n<p>Explanation:<br \/>\nWe Know the double\u00a0 6 + 6 = 12 , The number 7 is one more than 6,<br \/>\nSo we can write 7 as 6 + 1, The required sum is one more than double,<br \/>\n12 + 1 =13, Sum is 13, therefore 6 + 7 = 13, Double plus 1.<\/p>\n<p>6 + 5 = _______<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24635\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-132.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 132\" width=\"98\" height=\"51\" \/><br \/>\nAnswer:<br \/>\n6 + 5 = 11<\/p>\n<p>Explanation:<br \/>\nWe Know the double of 6 + 6 = 12 , The number 5 is one less than 6,<br \/>\nSo we can write 5 as 6 &#8211; 1, The required sum is one less than double,<br \/>\n12 &#8211; 1 = 11, Sum is 11, therefore 6 + 5 = 11, Double minus 1.<\/p>\n<p>Find the sum. Write the double you used.<\/p>\n<p>Question 4.<br \/>\n7 + 8 = _______<\/p>\n<p>____7_____ \u25cb ____8____ = ___15____<br \/>\nAnswer:<\/p>\n<p>7 + 8 = 15, 7 + 7 double is used<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-27447 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-4.bmp\" alt=\"\" width=\"441\" height=\"119\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-4.bmp 441w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-4-300x81.jpg 300w\" sizes=\"(max-width: 441px) 100vw, 441px\" \/><\/p>\n<p>Explanation:<br \/>\nAs the first addend is 7 and we know the double of 7 + 7 = 14 ,<br \/>\nThe number 8 is one more than 7, So we can write 8 as 7 + 1,<br \/>\nThe required sum is one more than double,<br \/>\n14 + 1 =15, Sum is 15, therefore 7 + 8 = 15, we used the double 7 +7.<\/p>\n<p>Question 5.<br \/>\n10 + 9 = ___19______<\/p>\n<p>_________ \u25cb ________ = _______<br \/>\nAnswer:<br \/>\n10 + 9 = 19, we use double 10 + 10,<\/p>\n<p>Explanation:<br \/>\nAs the first addend is 10 and we know the double is 10 + 10,<br \/>\n10 + 10 = 20 , The number 9 is one less than 10,<br \/>\nSo we can write 9 as 10 &#8211; 1, The required sum is one less than double,<br \/>\n20 &#8211; 1 = 19, Sum is 19, therefore 10 + 9 = 17, Double minus 1.<br \/>\nWe have use double 10 + 10 .<\/p>\n<h3><a id=\"count_on_to_within_20_Homework_&amp;_Practice_4.3\"><\/a>Count on to Add within 20 Homework &amp; Practice 4.3<\/h3>\n<p>Question 6.<br \/>\n11 + 6 = ___17____<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24634\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-133.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 133\" width=\"422\" height=\"42\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-133.png 422w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-133-300x30.png 300w\" sizes=\"(max-width: 422px) 100vw, 422px\" \/><br \/>\nAnswer:<\/p>\n<p>11 + 6 = 17<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29846 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-38.bmp\" alt=\"\" width=\"422\" height=\"149\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-38.bmp 422w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-38-300x106.jpg 300w\" sizes=\"(max-width: 422px) 100vw, 422px\" \/><br \/>\nExplanation:<br \/>\nFirst we start from 11 and move 6 units we get 17 on the number line,<br \/>\nSo sum is 11 +6 = 17 .<\/p>\n<h3><a id=\"Add_Three_Numbers_Homework_&amp;_Practice_4.4\"><\/a>Add Three Numbers Homework &amp; Practice 4.4<\/h3>\n<p>Question 7.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24633\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-134.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 134\" width=\"514\" height=\"120\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-134.png 514w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-134-300x70.png 300w\" sizes=\"(max-width: 514px) 100vw, 514px\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29855 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-39.bmp\" alt=\"\" width=\"514\" height=\"149\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-39.bmp 514w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-39-300x87.jpg 300w\" sizes=\"(max-width: 514px) 100vw, 514px\" \/><br \/>\n6 + 4 + 4 = 14<\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 4 + 4 = 8 and now we add 6 + 8 we get 14.<br \/>\nb. Here we add 6 + 4 = 10, now we add 10 + 4 =14,<br \/>\nc. Now here we add first 6 with 4 we get 10 to 10 we add 4<br \/>\nwe will get 10 + 4 = 14, So we get sum as 14.<\/p>\n<p>Question 8.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24632\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-135.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 135\" width=\"165\" height=\"82\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29857 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-40.bmp\" alt=\"\" width=\"529\" height=\"162\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-40.bmp 529w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-40-300x92.jpg 300w\" sizes=\"(max-width: 529px) 100vw, 529px\" \/><br \/>\n7 + 8 + 5 = 20<\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 7 + 8 = 15 and now we add 15+ 5 we get 20.<br \/>\nb. Here we add 8 + 5 = 13, now we add 13 + 7 =20,<br \/>\nc. Now here we add first 7 with 5 we get 12 to 12 we add 8<br \/>\nwe will get 12 + 8 = 20, So we get sum as 20.<\/p>\n<p>Question 9.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24631\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-136.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 136\" width=\"160\" height=\"77\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29902 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-42.bmp\" alt=\"\" width=\"514\" height=\"149\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-42.bmp 514w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-42-300x87.jpg 300w\" sizes=\"(max-width: 514px) 100vw, 514px\" \/><br \/>\n9 + 8 + 1 = 18<\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 9 + 8 = 17 and now we add 17 + 1 we get 18.<br \/>\nb. Here we add 8 + 1 =9, now we add 9 + 9 =18,<br \/>\nc. Now here we add first 9 with 1 we get 10 to 10 we add 8<br \/>\nwe will get 10 + 8 = 18, So we get sum as 18.<\/p>\n<p>Question 10.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24630\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-137.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 137\" width=\"165\" height=\"78\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29903 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-43.bmp\" alt=\"\" width=\"514\" height=\"149\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-43.bmp 514w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-43-300x87.jpg 300w\" sizes=\"(max-width: 514px) 100vw, 514px\" \/><br \/>\n2 + 3 + 5 = 10<\/p>\n<p>Explanation:<br \/>\nBy using linking the cubes<br \/>\na. First we add 2 + 3 = 5 and now we add 5 + 5 we get 10.<br \/>\nb. Here we add 3 + 5 =8, now we add 8 + 2 =10,<br \/>\nc. Now here we add first 2 with 5 we get 7 to 7 we add 3<br \/>\nwe will get 7 + 3 = 10, So we get sum as 10.<\/p>\n<h3><a id=\"Add_Three_Numbers_by_making_a_10_Homework_&amp;_Practice_4.5\"><\/a>Add Three Numbers by Making a 10 Homework &amp; Practice 4.5<\/h3>\n<p>Make a 10 to add.<\/p>\n<p>Question 11.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24629\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-138.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 138\" width=\"171\" height=\"111\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29905 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-44.bmp\" alt=\"\" width=\"192\" height=\"141\" \/><br \/>\nAdd 7,3 first to make 10 then add 9, sum = 7 + 9 + 3 = 19<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 7 + 9 = 16 is not equal to 10,<br \/>\nnext we add 9 + 3 = 12 not equal to 10, 7 + 3 = 10 which<br \/>\nis equal to 10 ,So to make 10 we add\u00a0 7,3 first, then add 9,<br \/>\nSo the sum is 7 + 9 + 3 = 19.<\/p>\n<p>Question 12.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24628\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-139.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 139\" width=\"165\" height=\"113\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29906 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-45.bmp\" alt=\"\" width=\"192\" height=\"141\" \/><\/p>\n<p>Add 9,1 first to make 10 then add 4, sum = 4 + 9 + 1 = 14<\/p>\n<p>Explanation:<br \/>\nTo make 10 first we see adding 4 + 9 = 13 is not equal to 10,<br \/>\nnext we add 9 + 1 = 10 is equal to 10, 4 + 1 = 5 which<br \/>\nis not equal to 10 ,So to make 10 we add\u00a0 9,1 first, then add 4,<br \/>\nSo the sum is 4 + 9 + 1 = 14.<\/p>\n<p>Question 13.<br \/>\n<strong>MP Number Sense<\/strong><br \/>\nWhat do you know about the missing addends and the sum?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24627\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-140.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 140\" width=\"145\" height=\"182\" \/><br \/>\nAnswer:<br \/>\nWe know the sum of the missing addends is 10 and the total sum is 10 + 5 = 15.<\/p>\n<p>Explanation:<br \/>\nFrom the picture it is showing that if we add the missing<br \/>\naddends we get sum as 10 and the total sum is 10 + 5 = 15.<br \/>\nSo whenever we are adding two missing addends we should always check,<br \/>\ntheir sum should be always 10, Example if one number is 1<br \/>\nother number will be 10-1 = 9. So the missing numbers are (1,9).<br \/>\nIt can be even (2,8), (3,7),(4,6),(5,5),(6,4),(7,3),(8,2) or (9,1).<\/p>\n<h3><a id=\"Add_9_Homework_&amp;_Practice_4.6\"><\/a>Add 9 Homework &amp; Practice 4.6<\/h3>\n<p>Question 14.<br \/>\nMake a 10 to add 9 + 4.<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24626\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-141.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 141\" width=\"267\" height=\"117\" \/><br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24625\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-142.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 142\" width=\"183\" height=\"166\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29907 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-46.bmp\" alt=\"\" width=\"192\" height=\"166\" \/><\/p>\n<p>Sum as 9 + 1 + 3 = 13\u00a0 or 9 + 4 = 13.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10 , For 9 to make 10 we need 10-9=1,<br \/>\nas we have to\u00a0 add 1 to 9 now\u00a0 we will minus 1 from 4 we get 4 &#8211; 1 = 3,<br \/>\nNow we write the total sum as 9 + 1 + 3 = 13\u00a0 or 9 + 4 = 13.<\/p>\n<h3><a id=\"making_a_10_to_add_homework_&amp;_Practice_4.7\"><\/a>Make a 10 to Add Homework &amp; Practice 4.7<\/h3>\n<p>Question 15.<br \/>\nMake a 10 to add 8 + 5.<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-24624 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-143.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 143\" width=\"477\" height=\"169\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-143.png 477w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-143-300x106.png 300w\" sizes=\"(max-width: 477px) 100vw, 477px\" \/><br \/>\nAnswer:<br \/>\n<a href=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-47.bmp\"><img loading=\"lazy\" class=\"alignnone wp-image-29909\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-47-300x106.jpg\" alt=\"\" width=\"481\" height=\"170\" srcset=\"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-47-300x106.jpg 300w, https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-47.bmp 477w\" sizes=\"(max-width: 481px) 100vw, 481px\" \/><\/a><br \/>\nSum as 8 + 2 + 3 = 13\u00a0 or 8 + 5 = 13.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10 , For 8 to make 10 we need 10-8=2,<br \/>\nas we have to\u00a0 add 2 to 8 now\u00a0 we will minus 2 from 5 we get 5 &#8211; 2 = 3,<br \/>\nNow we write the total sum as 8 + 2 + 3 = 13\u00a0 or 8 + 5 = 13.<\/p>\n<p>Question 16.<br \/>\n7 + 7 = ?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24623\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-144.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 144\" width=\"177\" height=\"167\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29910 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-48.bmp\" alt=\"\" width=\"211\" height=\"165\" \/><\/p>\n<p>Sum as 7 + 3 + 4\u00a0 = 14 or 7 + 7 = 14.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10, For 7 to make 10 we need 10-7=3,<br \/>\nas we have to add 3 to 7 now we will minus 3 from 7 we get 7 &#8211; 3 = 4,<br \/>\nNow we write the total sum as 7 + 3 + 4\u00a0 = 14 or 7 + 7 = 14.<\/p>\n<p>Question 17.<br \/>\n9 + 8 = ?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24622\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-145.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 145\" width=\"180\" height=\"168\" \/><br \/>\nAnswer:<br \/>\n<img loading=\"lazy\" class=\"alignnone wp-image-29911 size-full\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/4-Add-Numbers-49.bmp\" alt=\"\" width=\"211\" height=\"168\" \/><\/p>\n<p>Sum as 9 + 1 + 7\u00a0 = 17 or 9 + 8 = 17.<\/p>\n<p>Explanation:<br \/>\nFirst we make sum 10, For 9 to make 10 we need 10-9=1,<br \/>\nas we have to add 1 to 9 now we will minus 1 from 8 we get 8 &#8211; 1 = 7,<br \/>\nNow we write the total sum as 9 + 1 + 7\u00a0 = 17 or 9 + 8 = 17.<\/p>\n<h3><a id=\"Problem_Solving:_Addition_within_20_homework_&amp;_Practice_4.8\"><\/a>Problem Solving: Addition within 20 Homework &amp; Practice 4.8<\/h3>\n<p>Question 18.<br \/>\n<strong>Modeling Real Life<\/strong><br \/>\nYour friend finds 7 insects. You find 9 more than your friend. How many insects do you find?<br \/>\n<img loading=\"lazy\" class=\"alignnone size-full wp-image-24621\" src=\"https:\/\/ccssmathanswers.com\/wp-content\/uploads\/2021\/01\/Big-Ideas-Math-Solutions-Grade-1-Chapter-4-Add-Numbers-within-20-146.png\" alt=\"Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 146\" width=\"103\" height=\"83\" \/><\/p>\n<p>_____16____ insects<br \/>\nAnswer:<br \/>\nI found <span style=\"text-decoration: underline;\">16 <\/span> insects.<\/p>\n<p>Explanation:<br \/>\nGiven a friend finds 7 insects, I find 9 more than my friend means<br \/>\nI have in total as 7 + 9 = 16 insects,<br \/>\nSo I found <span style=\"text-decoration: underline;\">16 <\/span> insects.<\/p>\n<p>Conclusion:<\/p>\n<p>Learn the Big Ideas Math Book 1st Grade Answer Key Chapter 4 Add Numbers within 20 provided and improve your math as well as problem solving skills. You can achieve greater heights and fall in love with Math with our Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20. Stay with us to get the solutions of all Big Ideas Math Grade 1 Chapters from 1 to 14.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In Order to attempt the 1st Grade Exam, you need to have strong fundamentals. Download Big Ideas Math Book 1st Grade Answer Key Chapter 4 Add Numbers within 20 free of cost and get the homework help you need. Attempt the practice test to know your preparation level within the Chapter. Practice as much as &#8230; <a title=\"Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20\" class=\"read-more\" href=\"https:\/\/bigideasmathanswers.com\/big-ideas-math-answers-grade-1-chapter-4\/\" aria-label=\"More on Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20\">Read more<\/a><\/p>\n","protected":false},"author":8,"featured_media":89526,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":""},"categories":[4],"tags":[],"jetpack_featured_media_url":"https:\/\/bigideasmathanswers.com\/wp-content\/uploads\/2021\/04\/Big-Ideas-Math-Answers-Grade-1-Chapter-4.png","_links":{"self":[{"href":"https:\/\/bigideasmathanswers.com\/wp-json\/wp\/v2\/posts\/23923"}],"collection":[{"href":"https:\/\/bigideasmathanswers.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bigideasmathanswers.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bigideasmathanswers.com\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/bigideasmathanswers.com\/wp-json\/wp\/v2\/comments?post=23923"}],"version-history":[{"count":1,"href":"https:\/\/bigideasmathanswers.com\/wp-json\/wp\/v2\/posts\/23923\/revisions"}],"predecessor-version":[{"id":90325,"href":"https:\/\/bigideasmathanswers.com\/wp-json\/wp\/v2\/posts\/23923\/revisions\/90325"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/bigideasmathanswers.com\/wp-json\/wp\/v2\/media\/89526"}],"wp:attachment":[{"href":"https:\/\/bigideasmathanswers.com\/wp-json\/wp\/v2\/media?parent=23923"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bigideasmathanswers.com\/wp-json\/wp\/v2\/categories?post=23923"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bigideasmathanswers.com\/wp-json\/wp\/v2\/tags?post=23923"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}