Year 7 Estimating Sums, Differences and Products Worksheet — Level 1 — Practice Set 4 — Answers
Answer sheet with worked solutions for the Year 7 place value worksheet.
Success TutoringWorksheetsAnswer sheetYear 7 · Mathematics · Place ValueYear 7 Estimating Sums, Differences and Products Worksheet — Level 1 — Practice Set 4 — Answers
Round each number first, then work out the estimate in your head.
1.Estimate 82 − 51 by rounding each number to the nearest 10.
Answer: 30
- 82 rounds to 80; 51 rounds to 50
- 80 − 50 = 30
The exact answer is 31, close to the estimate.
2.Estimate 18 + 15 by rounding each number to the nearest 10.
Answer: 40
- 18 rounds to 20; 15 rounds to 20
- 20 + 20 = 40
The exact answer is 33, close to the estimate.
3.Estimate 21 + 36 by rounding each number to the nearest 10.
Answer: 60
- 21 rounds to 20; 36 rounds to 40
- 20 + 40 = 60
The exact answer is 57, close to the estimate.
4.Estimate 76 + 94 by rounding each number to the nearest 10.
Answer: 170
- 76 rounds to 80; 94 rounds to 90
- 80 + 90 = 170
The exact answer is 170, close to the estimate.
5.Estimate 94 + 79 by rounding each number to the nearest 10.
Answer: 170
- 94 rounds to 90; 79 rounds to 80
- 90 + 80 = 170
The exact answer is 173, close to the estimate.
6.Estimate 66 − 25 by rounding each number to the nearest 10.
Answer: 40
- 66 rounds to 70; 25 rounds to 30
- 70 − 30 = 40
The exact answer is 41, close to the estimate.
7.Estimate 47 − 23 by rounding each number to the nearest 10.
Answer: 30
- 47 rounds to 50; 23 rounds to 20
- 50 − 20 = 30
The exact answer is 24, close to the estimate.
8.Estimate 68 − 18 by rounding each number to the nearest 10.
Answer: 50
- 68 rounds to 70; 18 rounds to 20
- 70 − 20 = 50
The exact answer is 50, close to the estimate.
9.Estimate 66 + 25 by rounding each number to the nearest 10.
Answer: 100
- 66 rounds to 70; 25 rounds to 30
- 70 + 30 = 100
The exact answer is 91, close to the estimate.
10.Estimate 14 + 81 by rounding each number to the nearest 10.
Answer: 90
- 14 rounds to 10; 81 rounds to 80
- 10 + 80 = 90
The exact answer is 95, close to the estimate.
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.