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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 701 · 40 questions
TalentJR

How to do it in your head (Round, then work): Round each number: 2-digit numbers to the nearest ten, 3-digit numbers to the nearest hundred. Do the easy sum with the round numbers. Choose the option closest to your estimate.

NameDateTime takenScore ___ / 40
  1. 1.Best estimate of 14 × 58? (a) 60 (b) 6000 (c) 600
  2. 2.Best estimate of 482 + 736? (a) 1000 (b) 1200 (c) 1400
  3. 3.Best estimate of 475 + 707? (a) 1400 (b) 1200 (c) 1000
  4. 4.Best estimate of 48 × 20? (a) 1000 (b) 100 (c) 10000
  5. 5.Best estimate of 91 × 63? (a) 5400 (b) 540 (c) 54000
  6. 6.Best estimate of 76 × 73? (a) 5600 (b) 56000 (c) 560
  7. 7.Best estimate of 22 × 23? (a) 400 (b) 40 (c) 4000
  8. 8.Best estimate of 849 + 653? (a) 1700 (b) 1300 (c) 1500
  9. 9.Best estimate of 811 + 800? (a) 1600 (b) 1800 (c) 1400
  10. 10.Best estimate of 46 × 19? (a) 1000 (b) 100 (c) 10000
  11. 11.Best estimate of 23 × 63? (a) 1200 (b) 12000 (c) 120
  12. 12.Best estimate of 86 × 46? (a) 45000 (b) 450 (c) 4500
  13. 13.Best estimate of 680 + 149? (a) 800 (b) 1000 (c) 600
  14. 14.Best estimate of 759 + 739? (a) 1700 (b) 1300 (c) 1500
  15. 15.Best estimate of 12 × 18? (a) 200 (b) 2000 (c) 20
  16. 16.Best estimate of 30 × 54? (a) 15000 (b) 150 (c) 1500
  17. 17.Best estimate of 299 + 659? (a) 800 (b) 1000 (c) 1200
  18. 18.Best estimate of 59 × 39? (a) 240 (b) 2400 (c) 24000
  19. 19.Best estimate of 870 + 717? (a) 1400 (b) 1800 (c) 1600
  20. 20.Best estimate of 27 × 18? (a) 600 (b) 60 (c) 6000
  21. 21.Best estimate of 547 + 513? (a) 1200 (b) 1000 (c) 800
  22. 22.Best estimate of 46 × 31? (a) 1500 (b) 15000 (c) 150
  23. 23.Best estimate of 27 × 64? (a) 18000 (b) 180 (c) 1800
  24. 24.Best estimate of 89 × 17? (a) 18000 (b) 180 (c) 1800
  25. 25.Best estimate of 52 × 72? (a) 3500 (b) 35000 (c) 350
  26. 26.Best estimate of 317 + 319? (a) 600 (b) 400 (c) 800
  27. 27.Best estimate of 26 × 61? (a) 18000 (b) 1800 (c) 180
  28. 28.Best estimate of 93 × 46? (a) 4500 (b) 450 (c) 45000
  29. 29.Best estimate of 19 × 30? (a) 600 (b) 60 (c) 6000
  30. 30.Best estimate of 69 × 64? (a) 42000 (b) 4200 (c) 420
  31. 31.Best estimate of 79 × 36? (a) 32000 (b) 3200 (c) 320
  32. 32.Best estimate of 36 × 31? (a) 120 (b) 1200 (c) 12000
  33. 33.Best estimate of 94 × 71? (a) 6300 (b) 630 (c) 63000
  34. 34.Best estimate of 571 + 861? (a) 1500 (b) 1700 (c) 1300
  35. 35.Best estimate of 434 + 486? (a) 900 (b) 1100 (c) 700
  36. 36.Best estimate of 233 + 502? (a) 500 (b) 900 (c) 700
  37. 37.Best estimate of 529 + 143? (a) 400 (b) 800 (c) 600
  38. 38.Best estimate of 31 × 13? (a) 3000 (b) 300 (c) 30
  39. 39.Best estimate of 14 × 28? (a) 3000 (b) 30 (c) 300
  40. 40.Best estimate of 875 + 409? (a) 1300 (b) 1100 (c) 1500

Answer key

  1. 600
  2. 1200
  3. 1200
  4. 1000
  5. 5400
  6. 5600
  7. 400
  8. 1500
  9. 1600
  10. 1000
  11. 1200
  12. 4500
  13. 800
  14. 1500
  15. 200
  16. 1500
  17. 1000
  18. 2400
  19. 1600
  20. 600
  21. 1000
  22. 1500
  23. 1800
  24. 1800
  25. 3500
  26. 600
  27. 1800
  28. 4500
  29. 600
  30. 4200
  31. 3200
  32. 1200
  33. 6300
  34. 1500
  35. 900
  36. 700
  37. 600
  38. 300
  39. 300
  40. 1300

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