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Lesson 5.1 Name Algebra • Break Apart Ones to Subtract Essential Question How does breaking apart a number make subtracting easier? Number and Operations in Base Ten—2.NBT.B.5 MATHEMATICAL PRACTICES MP1, MP5, MP6 Listen Listen and and Draw Draw © Houghton Mifflin Harcourt Publishing Company Write two addends for each sum. 7 9 5 6 4 8 Math Talk FOR THE TEACHER • After children have recorded addends for each sum, have a class discussion about the different facts that children represented on their papers. Chapter 5 MATHEMATICAL PRACTICES 6 Describe how you chose addends for each sum. three hundred seventeen 317 Model Model and and Draw Draw Break apart ones. Subtract in two steps. Start at 63. Subtract 3 to get to 60. Then subtract 4 more. 63 − 7 = ■ 3 4 -4 -3 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 So, 63 − 7 = —. Share hhow Share and and Show Sh MATH M BOARD B Break apart ones to subtract. Write the difference. 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 55 − 8 = — 5 2. 3 42 − 5 = — 2 3 3. 41 − 9 = — 4. 53 − 6 = — 5. 44 − 7 = — 6. 52 − 8 = — 318 three hundred eighteen © Houghton Mifflin Harcourt Publishing Company 1. Name On On Your Your Own Own Break apart ones to subtract. Write the difference. 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 7. 75 − 7 = — 8. 86 − 8 = — 9. 82 − 5 = — 10. 83 − 7 = — 11. 72 − 7 = — 12. 76 − 9 = — 13. 85 − 8 = — 14. 71 − 6 = — © Houghton Mifflin Harcourt Publishing Company • Image Credits: (b) Artville/Getty Images 15. 16. SMARTER Cheryl brought 27 bagels for the bake sale. Mike brought 24 bagels. They sold all but 9 of them. How many bagels did they sell? MATHEMATICAL PRACTICE — bagels 1 Analyze Lexi has 8 fewer crayons than Ken. Ken has 45 crayons. How many crayons does Lexi have? Chapter 5 • Lesson 1 — crayons three hundred nineteen 319 MATHEMATICAL PRACTICES COMMUNICAK<G<IJ<M<I<CFEJKIL:K8I>LD<EKJ Math OqnakdlRnkuhmf¤@ookhb`shnmr OqnakdlRnkuhmf¤@ookhb`shnmr Write or draw to explain. 17. Cheryl built a toy train with 27 train cars. Then she added 18 more train cars. How many train cars are on the toy train now? — train cars 18. MATHEMATICAL PRACTICE 1 Analyze Samuel had 46 marbles. He gave some marbles to a friend and has 9 marbles left. How many marbles did Samuel give to his friend? 19. — marbles SMARTER Matthew had 73 blocks. He gave 8 blocks to his sister. How many blocks does Matthew have now? Matthew has — blocks now. TAKE HOME ACTIVITY • Ask your child to describe how to find 34 − 6. 320 three hundred twenty © Houghton Mifflin Harcourt Publishing Company Draw or write to show how to solve the problem. Practice and Homework Name Lesson 5.1 Algebra • Break Apar t Ones to Subtract COMMON CORE STANDARD—2.NBT.B.5 Use place value understanding and properties of operations to add and subtract. Break apart ones to subtract. Write the difference. 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 1. 36 − 7 = 3. 37 − 9 = 5. 44 − 5 = 7. 32 − 4 = — — — — 2. 35 − 8 = 4. 41 − 6 = 6. 33 − 7 = 8. 31 − 6 = — — — — Problem Problem Solving Solving Choose a way to solve. Write or draw to explain. 9. Beth had 44 marbles. She gave © Houghton Mifflin Harcourt Publishing Company 9 marbles to her brother. How many marbles does Beth have now? — marbles 10. Math Draw a number line and show how to find the difference for 24 – 6 using the break apart method in this lesson. Chapter 5 three hundred twenty-one 321 Lesson Check (2.NBT.B.5) 1. What is the difference? 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 58 − 9 = (2.OA.B.2, 2.NBT.B.6) 2. What is the difference? 14 − 6 = — 4. What is the sum? 64 + 7 = 322 — 3. What is the sum? 3 + 6 +2 = — 5. What is the sum? 56 + 18 = — FOR MORE PRACTICE GO TO THE three hundred twenty-two Personal Math Trainer © Houghton Mifflin Harcourt Publishing Company Spiral Review —