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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 752 · 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 176 + 863? (a) 1100 (b) 900 (c) 1300
  2. 2.Best estimate of 482 + 276? (a) 800 (b) 600 (c) 1000
  3. 3.Best estimate of 76 × 91? (a) 720 (b) 7200 (c) 72000
  4. 4.Best estimate of 67 × 16? (a) 14000 (b) 140 (c) 1400
  5. 5.Best estimate of 275 + 473? (a) 600 (b) 1000 (c) 800
  6. 6.Best estimate of 58 × 38? (a) 24000 (b) 2400 (c) 240
  7. 7.Best estimate of 618 + 440? (a) 1200 (b) 1000 (c) 800
  8. 8.Best estimate of 17 × 93? (a) 180 (b) 18000 (c) 1800
  9. 9.Best estimate of 19 × 60? (a) 12000 (b) 1200 (c) 120
  10. 10.Best estimate of 32 × 34? (a) 900 (b) 90 (c) 9000
  11. 11.Best estimate of 629 + 625? (a) 1400 (b) 1200 (c) 1000
  12. 12.Best estimate of 56 × 49? (a) 300 (b) 30000 (c) 3000
  13. 13.Best estimate of 86 × 16? (a) 180 (b) 1800 (c) 18000
  14. 14.Best estimate of 36 × 62? (a) 2400 (b) 24000 (c) 240
  15. 15.Best estimate of 36 × 18? (a) 80 (b) 8000 (c) 800
  16. 16.Best estimate of 61 × 31? (a) 18000 (b) 1800 (c) 180
  17. 17.Best estimate of 64 × 37? (a) 2400 (b) 24000 (c) 240
  18. 18.Best estimate of 60 × 47? (a) 30000 (b) 3000 (c) 300
  19. 19.Best estimate of 792 + 534? (a) 1100 (b) 1500 (c) 1300
  20. 20.Best estimate of 729 + 817? (a) 1500 (b) 1300 (c) 1700
  21. 21.Best estimate of 505 + 197? (a) 500 (b) 900 (c) 700
  22. 22.Best estimate of 255 + 206? (a) 700 (b) 500 (c) 300
  23. 23.Best estimate of 576 + 838? (a) 1400 (b) 1600 (c) 1200
  24. 24.Best estimate of 91 × 96? (a) 90000 (b) 9000 (c) 900
  25. 25.Best estimate of 22 × 31? (a) 6000 (b) 600 (c) 60
  26. 26.Best estimate of 83 × 14? (a) 800 (b) 8000 (c) 80
  27. 27.Best estimate of 623 + 295? (a) 900 (b) 700 (c) 1100
  28. 28.Best estimate of 391 + 234? (a) 400 (b) 600 (c) 800
  29. 29.Best estimate of 363 + 762? (a) 1200 (b) 1400 (c) 1000
  30. 30.Best estimate of 217 + 773? (a) 1200 (b) 1000 (c) 800
  31. 31.Best estimate of 251 + 707? (a) 1200 (b) 1000 (c) 800
  32. 32.Best estimate of 778 + 833? (a) 1600 (b) 1800 (c) 1400
  33. 33.Best estimate of 388 + 246? (a) 400 (b) 800 (c) 600
  34. 34.Best estimate of 49 × 76? (a) 40000 (b) 4000 (c) 400
  35. 35.Best estimate of 94 × 37? (a) 36000 (b) 360 (c) 3600
  36. 36.Best estimate of 70 × 19? (a) 140 (b) 14000 (c) 1400
  37. 37.Best estimate of 680 + 720? (a) 1200 (b) 1400 (c) 1600
  38. 38.Best estimate of 76 × 97? (a) 8000 (b) 80000 (c) 800
  39. 39.Best estimate of 204 + 761? (a) 800 (b) 1200 (c) 1000
  40. 40.Best estimate of 344 + 357? (a) 900 (b) 500 (c) 700

Answer key

  1. 1100
  2. 800
  3. 7200
  4. 1400
  5. 800
  6. 2400
  7. 1000
  8. 1800
  9. 1200
  10. 900
  11. 1200
  12. 3000
  13. 1800
  14. 2400
  15. 800
  16. 1800
  17. 2400
  18. 3000
  19. 1300
  20. 1500
  21. 700
  22. 500
  23. 1400
  24. 9000
  25. 600
  26. 800
  27. 900
  28. 600
  29. 1200
  30. 1000
  31. 1000
  32. 1600
  33. 600
  34. 4000
  35. 3600
  36. 1400
  37. 1400
  38. 8000
  39. 1000
  40. 700

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