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Lesson 5.2 Name Algebra • Break Apart Numbers to Subtract Number and Operations in Base Ten—2.NBT.B.5 MATHEMATICAL PRACTICES MP1, MP5, MP6 Essential Question How does breaking apart a number make subtracting easier? Listen Listen and and Draw Draw Draw jumps on the number line to show how to break apart the number to subtract. 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 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 © Houghton Mifflin Harcourt Publishing Company 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 Math Talk FOR THE TEACHER • Read the following problem. Have children draw jumps on the number line to solve. Mrs. Hill had 45 paintbrushes. She gave 9 paintbrushes to students in her art class. How many paintbrushes does Mrs. Hill have now? Repeat the same problem situation for 72 − 7 and 53 − 6. Chapter 5 MATHEMATICAL PRACTICES 6 Describe a Method For one of the problems, describe what you did. three hundred twenty-three 323 Model Model and and Draw Draw Break apart the number you are subtracting into tens and ones. Subtract 10. Next, subtract 2 to get to 60. Then subtract 5 more. 72 − 17 = ■ 10 2 10 + 2 + 5 = 17 -5 7 -2 5 -10 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 So, 72 − 17 = Share hhow Share and and Show Sh —. MATH M BOARD B Break apart the number you are subtracting. 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 43 − 18 = 10 45 − 14 = 10 — 4 5 46 − 17 = 324 2. 8 3 3. — — three hundred twenty-four 4. 44 − 16 = — © Houghton Mifflin Harcourt Publishing Company 1. Name On On Your Your Own Own Break apart the number you are subtracting. Write 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 5. 57 − 15 = — 6. 63 − 17 = — 7. 68 − 19 = — 8. 61 − 18 = — 9. © Houghton Mifflin Harcourt Publishing Company 10. SMARTER Jane has 53 toys in a box. She takes some toys out. Now there are 36 toys in the box. How many toys did Jane take out of the box? DEEPER Look at Tom’s steps to solve a problem. Solve this problem in the same way. 42 − 15 = ? — toys Tom 35 – 18 = ? 35 – 10 = 25 25 – 5 = 20 20 – 3 = 17 Chapter 5 • Lesson 2 three hundred twenty-ﬁve 325 MATHEMATICAL PRACTICES 8E8CPQ<CFFB=FIJKIL:KLI<GI<:@J@FE OqnakdlRnkuhmf¤@ookhb`shnmr OqnakdlRnkuhmf¤@ookhb`shnmr Math 11. 38 people are in the library. Then 33 more people go into the library. How many people are in the library now? — people 12. MATHEMATICAL PRACTICE 1 Analyze Alex has 24 toys in a chest. He takes some toys out of the chest. Then there are 16 toys in the chest. How many toys did he take out of the chest? 13. — toys SMARTER Gail has two piles of newspapers. There are 32 papers in the first pile. There are 19 papers in the second pile. How many more papers are in the first pile than in the second pile? — more papers TAKE HOME ACTIVITY • Ask your child to write a subtraction story that uses 2-digit numbers. 326 three hundred twenty-six © Houghton Mifflin Harcourt Publishing Company Write or draw to explain how you solved the problem. Practice and Homework Name Algebra • Break Apar t Numbers to Subtract Lesson 5.2 COMMON CORE STANDARD—2.NBT.B.5 Use place value understanding and properties of operations to add and subtract. Break apart the number you are subtracting. 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 1. 81 − 14 = — 2. 84 2 16 = — 3. 77 − 14 = — 4. 83 2 19 = — 5. 81 − 17 = — 6. 88 2 13 = — 7. 84 − 19 = — 8. 86 2 18 = — Problem Problem Solving Solving Solve. Write or draw to explain. 9. Mr . Pearce bought 43 plants. He gave © Houghton Mifflin Harcourt Publishing Company 14 plants to his sister . How many plants does Mr . Pearce have now? — plants 10. Math Draw a number line and show how to find the difference for 36 – 17 using the break apart method in this lesson. Chapter 5 three hundred twenty-seven 327 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 63 − 19 = — Spiral Review (2.OA.A.1, 2.OA.B.2, 2.NBT.B.6) 2. What is the sum? 14 + 23 4. Write a related subtraction fact for 6 + 8 = 14. 3. What is the sum? 8+7=— 5. John has 7 kites. Annie has 4 kites. How many kites do © Houghton Mifflin Harcourt Publishing Company they have altogether? — kites 328 FOR MORE PRACTICE GO TO THE three hundred twenty-eight Personal Math Trainer