## Trade first subtraction method ballpark estimate

estimate. Choose at least two problems to solve using the trade-first method and show your work. You may choose any method you wish to solve the other problems. Unit dollars Example: Ballpark estimate: Trade-First Method 250 200 50 1. Ballpark estimate: 74 29 2. Ballpark estimate: 96 37 5. Ballpark estimate: 826 172 4. Ballpark estimate: 271 248 3. Ballpark estimate: 208 106 Ballpark estimate: 1. Ballpark estimate: 40 - 20 = 20 2. Ballpark estimate: 3. Ballpark estimate: 4. Ballpark estimate: 5. Ballpark estimate: LESSON11 Trade-First Subtraction 3 Date Time longs cubes 10s 1s 2 17 3 7 - 1 9 1 8 Make a ballpark estimate for each problem and write a number model for your ballpark estimate. LESSON Trade-First Subtraction 3 Date Time longs cubes 10s 1s 76 59 longs cubes 10s 1s 35 26 longs cubes 10s 1s 44 27 longs cubes 10s 1s 217 37 1919 18 Make a ballpark estimate for each problem and write a number model for your ballpark estimate. Use the trade-first method of subtraction to solve each problem. 28 31 17 Answer 9 Answer 14 Answer 9 Answer 17 Answer 17 18 Example: HOME LINK 5 12 Make a ballpark estimate. Subtract and show your work. Check to see if your answer makes sense. 1. Use the counting-up method. 754 -299 2. Use the trade-first method. 754 -299 Multiplication. Write facts that you know. 3. × 2 facts 4. × 3 facts 5.× 4 facts 4 × 2= 8 161 Subtraction & Multiplication Practice Unit Solve Problems 1–3 using the trade-first method. Solve Problems 4–6 using any method. Use your ballpark estimates to see if your answers make sense. Sample estimates: 12 13 1. 58 39 Ballpark estimate: 60 40 20 19 2. 600 379 Ballpark estimate: 600 400 200 221 3. 2,936 1,657 Ballpark estimate: 3,000 2,000 1,000 1,279 4. 73 37 Ballpark estimate: 70 40 30 36 5. 900 461

## Trade First Subtraction Method. This method is most commonly used in the United States and most parents learned to subtract in a way that is very similar to this

Solve Problems 1–3 using the trade-first method. Solve Problems 4–6 using any method. Use your ballpark estimates to see if your answers make sense. Sample estimates: 12 13 1. 58 39 Ballpark estimate: 60 40 20 19 2. 600 379 Ballpark estimate: 600 400 200 221 3. 2,936 1,657 Ballpark estimate: 3,000 2,000 1,000 1,279 4. 73 37 Ballpark estimate: 70 40 30 36 5. 900 461 Name Date Time Make a ballpark estimate. Use the trade-first subtraction methodto subtract. Compare your answer with your estimate to see if your answer makes sense. 7. 8 64 8. 9 72 9. 56 8 10. 42 7 Practice. 1. 2. 3. Discuss children’s solutions to Problem 1 on journal page 5P. 93 - 58 = 35 blocks Expect that children will use several different methods, which may include modeling with base-10 blocks or other manipulatives, applying various paper-and-pencil methods such as counting up, and using trade-first subtraction. The answer is 7. Make a ballpark estimate to see whether the answer makes sense: 46 is close to 50, and 39 is close to 40. 50 - 40 = 10. 10 is close to the answer of 7, so 7 is a reasonable answer. The trade-first method is one of many ways people solve subtraction problems. Students will use the trade-first algorithm to subtract 2 and 3-digit numbers. They will make ballpark estimate to check subtraction results. Grade level 3, 20 students, one student with visual impairment, one ELL student . Objectives. Students will be able to subtract two 3-digit numbers using the trade-first algorithm

### 00s Subtraction Methods Make a ballpark estimate. Write a number model to show your estimate. Choose at least two problems to solve using the trade-first

Ballpark estimate: 1. Ballpark estimate: 40 - 20 = 20 2. Ballpark estimate: 3. Ballpark estimate: 4. Ballpark estimate: 5. Ballpark estimate: LESSON11 Trade-First Subtraction 3 Date Time longs cubes 10s 1s 2 17 3 7 - 1 9 1 8 Make a ballpark estimate for each problem and write a number model for your ballpark estimate. LESSON Trade-First Subtraction 3 Date Time longs cubes 10s 1s 76 59 longs cubes 10s 1s 35 26 longs cubes 10s 1s 44 27 longs cubes 10s 1s 217 37 1919 18 Make a ballpark estimate for each problem and write a number model for your ballpark estimate. Use the trade-first method of subtraction to solve each problem. 28 31 17 Answer 9 Answer 14 Answer 9 Answer 17 Answer 17 18 Example: HOME LINK 5 12 Make a ballpark estimate. Subtract and show your work. Check to see if your answer makes sense. 1. Use the counting-up method. 754 -299 2. Use the trade-first method. 754 -299 Multiplication. Write facts that you know. 3. × 2 facts 4. × 3 facts 5.× 4 facts 4 × 2= 8 161 Subtraction & Multiplication Practice Unit Solve Problems 1–3 using the trade-first method. Solve Problems 4–6 using any method. Use your ballpark estimates to see if your answers make sense. Sample estimates: 12 13 1. 58 39 Ballpark estimate: 60 40 20 19 2. 600 379 Ballpark estimate: 600 400 200 221 3. 2,936 1,657 Ballpark estimate: 3,000 2,000 1,000 1,279 4. 73 37 Ballpark estimate: 70 40 30 36 5. 900 461

### Make a ballpark estimate. Use the trade-first subtraction method to subtract. Compare your answer with your estimate to see if your answer makes sense. 7. 8 × = 64 8. 9 ×== 72 9. 56 × 8 10. 42 = 7 Practice 1. 2. 3. Ballpark estimate: Ballpark estimate: Ballpark estimate: 4. 5. 6. Ballpark estimate: Ballpark estimate: Ballpark estimate: 96 - -28 469 - 87 732

Subtraction Across Zeros Tutorial-Box-it Method - Duration: 9:56. jlburnell 53,427 views Solve Problems 1–3 using the trade-first method. Solve Problems 4–6 using any method. Use your ballpark estimates to see if your answers make sense. Sample estimates: 12 13 1. 58 39 Ballpark estimate: 60 40 20 19 2. 600 379 Ballpark estimate: 600 400 200 221 3. 2,936 1,657 Ballpark estimate: 3,000 2,000 1,000 1,279 4. 73 37 Ballpark estimate: 70 40 30 36 5. 900 461 Make a ballpark estimate. Use the trade-first subtraction method to subtract. Compare your answer with your estimate to see if your answer makes sense. 7. 8 × ×= 64 8. 9 == 72 9. 56 × 8 10. 42 = × 7 Practice 1. 2. 3. Ballpark estimate: Ballpark estimate: Ballpark estimate: 4. 5. 6. Ballpark estimate: Ballpark estimate: Ballpark estimate: 96 - 28 469 - 87 LESSON Trade-First Subtraction 3 Date Time longs cubes 10s 1s 76 59 longs cubes 10s 1s 35 26 longs cubes 10s 1s 44 27 longs cubes 10s 1s 217 37 1919 18 Make a ballpark estimate for each problem and write a number model for your ballpark estimate. Use the trade-first method of subtraction to solve each problem. 28 31 17 Answer 9 Answer 14 Answer 9 Answer 17 Answer 17 18 Example: Make a ballpark estimate. Use the trade-first subtraction method to subtract. Compare your answer with your estimate to see if your answer makes sense. 7. 8 × = 64 8. 9 ×== 72 9. 56 × 8 10. 42 = 7 Practice 1. 2. 3. Ballpark estimate: Ballpark estimate: Ballpark estimate: 4. 5. 6. Ballpark estimate: Ballpark estimate: Ballpark estimate: 96 - -28 469 - 87 732 HOME LINK 5 12 Make a ballpark estimate. Subtract and show your work. Check to see if your answer makes sense. 1. Use the counting-up method. 754 -299 2. Use the trade-first method. 754 -299 Multiplication. Write facts that you know. 3. × 2 facts 4. × 3 facts 5.× 4 facts 4 × 2= 8 161 Subtraction & Multiplication Practice Unit

## LESSON Trade-First Subtraction 3 Date Time longs cubes 10s 1s 76 59 longs cubes 10s 1s 35 26 longs cubes 10s 1s 44 27 longs cubes 10s 1s 217 37 1919 18 Make a ballpark estimate for each problem and write a number model for your ballpark estimate. Use the trade-first method of subtraction to solve each problem. 28 31 17 Answer 9 Answer 14 Answer 9 Answer 17 Answer 17 18 Example:

Trade First Subtraction - Duration: 2:54. Adventures of Becca's Classroom 43 views estimate. Choose at least two problems to solve using the trade-first method and show your work. You may choose any method you wish to solve the other problems. Unit dollars Example: Ballpark estimate: Trade-First Method 250 200 50 1. Ballpark estimate: 74 29 2. Ballpark estimate: 96 37 5. Ballpark estimate: 826 172 4. Ballpark estimate: 271 248 3. Ballpark estimate: 208 106

Ballpark estimate: 1. Ballpark estimate: 40 - 20 = 20 2. Ballpark estimate: 3. Ballpark estimate: 4. Ballpark estimate: 5. Ballpark estimate: LESSON11 Trade-First Subtraction 3 Date Time longs cubes 10s 1s 2 17 3 7 - 1 9 1 8 Make a ballpark estimate for each problem and write a number model for your ballpark estimate. The answer is 7. Make a ballpark estimate to see whether the answer makes sense: 46 is close to 50, and 39 is close to 40. 50 - 40 = 10. 10 is close to the answer of 7, so 7 is a reasonable answer. The trade-first method is one of many ways people solve subtraction problems. Subtraction Across Zeros Tutorial-Box-it Method - Duration: 9:56. jlburnell 53,427 views Solve Problems 1–3 using the trade-first method. Solve Problems 4–6 using any method. Use your ballpark estimates to see if your answers make sense. Sample estimates: 12 13 1. 58 39 Ballpark estimate: 60 40 20 19 2. 600 379 Ballpark estimate: 600 400 200 221 3. 2,936 1,657 Ballpark estimate: 3,000 2,000 1,000 1,279 4. 73 37 Ballpark estimate: 70 40 30 36 5. 900 461