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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 477 · 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 769 + 615? (a) 1600 (b) 1400 (c) 1200
  2. 2.Best estimate of 91 × 56? (a) 5400 (b) 54000 (c) 540
  3. 3.Best estimate of 707 + 323? (a) 1200 (b) 1000 (c) 800
  4. 4.Best estimate of 49 × 12? (a) 500 (b) 50 (c) 5000
  5. 5.Best estimate of 12 × 36? (a) 400 (b) 4000 (c) 40
  6. 6.Best estimate of 23 × 39? (a) 8000 (b) 800 (c) 80
  7. 7.Best estimate of 707 + 532? (a) 1000 (b) 1400 (c) 1200
  8. 8.Best estimate of 510 + 179? (a) 900 (b) 500 (c) 700
  9. 9.Best estimate of 77 × 81? (a) 64000 (b) 640 (c) 6400
  10. 10.Best estimate of 88 × 61? (a) 54000 (b) 5400 (c) 540
  11. 11.Best estimate of 94 × 98? (a) 9000 (b) 900 (c) 90000
  12. 12.Best estimate of 42 × 83? (a) 3200 (b) 32000 (c) 320
  13. 13.Best estimate of 47 × 32? (a) 1500 (b) 150 (c) 15000
  14. 14.Best estimate of 863 + 212? (a) 1300 (b) 1100 (c) 900
  15. 15.Best estimate of 76 × 46? (a) 400 (b) 40000 (c) 4000
  16. 16.Best estimate of 60 × 73? (a) 420 (b) 42000 (c) 4200
  17. 17.Best estimate of 17 × 57? (a) 1200 (b) 120 (c) 12000
  18. 18.Best estimate of 53 × 14? (a) 5000 (b) 500 (c) 50
  19. 19.Best estimate of 441 + 627? (a) 1200 (b) 1000 (c) 800
  20. 20.Best estimate of 728 + 860? (a) 1400 (b) 1800 (c) 1600
  21. 21.Best estimate of 714 + 208? (a) 1100 (b) 700 (c) 900
  22. 22.Best estimate of 809 + 122? (a) 1100 (b) 700 (c) 900
  23. 23.Best estimate of 28 × 84? (a) 2400 (b) 24000 (c) 240
  24. 24.Best estimate of 19 × 56? (a) 12000 (b) 120 (c) 1200
  25. 25.Best estimate of 507 + 521? (a) 1200 (b) 800 (c) 1000
  26. 26.Best estimate of 80 × 86? (a) 720 (b) 7200 (c) 72000
  27. 27.Best estimate of 66 × 56? (a) 42000 (b) 420 (c) 4200
  28. 28.Best estimate of 176 + 419? (a) 800 (b) 600 (c) 400
  29. 29.Best estimate of 428 + 446? (a) 1000 (b) 800 (c) 600
  30. 30.Best estimate of 843 + 233? (a) 1200 (b) 800 (c) 1000
  31. 31.Best estimate of 84 × 98? (a) 800 (b) 80000 (c) 8000
  32. 32.Best estimate of 515 + 558? (a) 900 (b) 1300 (c) 1100
  33. 33.Best estimate of 40 × 34? (a) 1200 (b) 120 (c) 12000
  34. 34.Best estimate of 86 × 23? (a) 180 (b) 18000 (c) 1800
  35. 35.Best estimate of 180 + 577? (a) 600 (b) 1000 (c) 800
  36. 36.Best estimate of 134 + 286? (a) 400 (b) 200 (c) 600
  37. 37.Best estimate of 62 × 16? (a) 1200 (b) 120 (c) 12000
  38. 38.Best estimate of 649 + 692? (a) 1100 (b) 1500 (c) 1300
  39. 39.Best estimate of 473 + 453? (a) 1200 (b) 1000 (c) 800
  40. 40.Best estimate of 29 × 22? (a) 600 (b) 6000 (c) 60

Answer key

  1. 1400
  2. 5400
  3. 1000
  4. 500
  5. 400
  6. 800
  7. 1200
  8. 700
  9. 6400
  10. 5400
  11. 9000
  12. 3200
  13. 1500
  14. 1100
  15. 4000
  16. 4200
  17. 1200
  18. 500
  19. 1000
  20. 1600
  21. 900
  22. 900
  23. 2400
  24. 1200
  25. 1000
  26. 7200
  27. 4200
  28. 600
  29. 800
  30. 1000
  31. 8000
  32. 1100
  33. 1200
  34. 1800
  35. 800
  36. 400
  37. 1200
  38. 1300
  39. 1000
  40. 600

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