Year 3 Estimating Sums, Differences and Products Worksheet — Level 2 — Practice Set 3 — Answers
Answer sheet with worked solutions for the Year 3 place value worksheet.
Success TutoringWorksheetsAnswer sheetYear 3 · Mathematics · Place ValueYear 3 Estimating Sums, Differences and Products Worksheet — Level 2 — Practice Set 3 — Answers
Round each number first, then work out the estimate in your head.
1.Estimate 315 + 908 by rounding each number to the nearest 100.
Answer: 1,200
- 315 rounds to 300; 908 rounds to 900
- 300 + 900 = 1,200
The exact answer is 1,223, close to the estimate.
2.Estimate 64 × 4 by rounding 64 to the nearest 10.
Answer: 240
- 64 rounds to 60
- 60 × 4 = 240
The exact answer is 256.
3.Estimate 246 − 147 by rounding each number to the nearest 100.
Answer: 100
- 246 rounds to 200; 147 rounds to 100
- 200 − 100 = 100
The exact answer is 99, close to the estimate.
4.Estimate 85 × 5 by rounding 85 to the nearest 10.
Answer: 450
- 85 rounds to 90
- 90 × 5 = 450
The exact answer is 425.
5.Estimate 868 − 779 by rounding each number to the nearest 100.
Answer: 100
- 868 rounds to 900; 779 rounds to 800
- 900 − 800 = 100
The exact answer is 89, close to the estimate.
6.Estimate 45 × 3 by rounding 45 to the nearest 10.
Answer: 150
- 45 rounds to 50
- 50 × 3 = 150
The exact answer is 135.
7.Estimate 975 + 958 by rounding each number to the nearest 100.
Answer: 2,000
- 975 rounds to 1,000; 958 rounds to 1,000
- 1,000 + 1,000 = 2,000
The exact answer is 1,933, close to the estimate.
8.Estimate 51 × 8 by rounding 51 to the nearest 10.
Answer: 400
- 51 rounds to 50
- 50 × 8 = 400
The exact answer is 408.
9.Estimate 969 + 811 by rounding each number to the nearest 100.
Answer: 1,800
- 969 rounds to 1,000; 811 rounds to 800
- 1,000 + 800 = 1,800
The exact answer is 1,780, close to the estimate.
10.Estimate 37 × 3 by rounding 37 to the nearest 10.
Answer: 120
- 37 rounds to 40
- 40 × 3 = 120
The exact answer is 111.
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.