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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 140 · 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 261 + 643? (a) 700 (b) 900 (c) 1100
  2. 2.Best estimate of 432 + 247? (a) 400 (b) 800 (c) 600
  3. 3.Best estimate of 36 × 54? (a) 20000 (b) 200 (c) 2000
  4. 4.Best estimate of 167 + 336? (a) 700 (b) 300 (c) 500
  5. 5.Best estimate of 29 × 37? (a) 120 (b) 1200 (c) 12000
  6. 6.Best estimate of 63 × 88? (a) 54000 (b) 540 (c) 5400
  7. 7.Best estimate of 294 + 811? (a) 1300 (b) 900 (c) 1100
  8. 8.Best estimate of 828 + 383? (a) 1200 (b) 1400 (c) 1000
  9. 9.Best estimate of 24 × 66? (a) 1400 (b) 14000 (c) 140
  10. 10.Best estimate of 374 + 436? (a) 600 (b) 800 (c) 1000
  11. 11.Best estimate of 97 × 89? (a) 9000 (b) 90000 (c) 900
  12. 12.Best estimate of 244 + 653? (a) 1100 (b) 700 (c) 900
  13. 13.Best estimate of 806 + 665? (a) 1500 (b) 1700 (c) 1300
  14. 14.Best estimate of 664 + 188? (a) 1100 (b) 900 (c) 700
  15. 15.Best estimate of 56 × 60? (a) 36000 (b) 360 (c) 3600
  16. 16.Best estimate of 49 × 28? (a) 150 (b) 15000 (c) 1500
  17. 17.Best estimate of 242 + 637? (a) 800 (b) 600 (c) 1000
  18. 18.Best estimate of 628 + 210? (a) 1000 (b) 800 (c) 600
  19. 19.Best estimate of 522 + 316? (a) 1000 (b) 600 (c) 800
  20. 20.Best estimate of 91 × 37? (a) 360 (b) 3600 (c) 36000
  21. 21.Best estimate of 441 + 648? (a) 800 (b) 1200 (c) 1000
  22. 22.Best estimate of 41 × 78? (a) 3200 (b) 32000 (c) 320
  23. 23.Best estimate of 13 × 43? (a) 400 (b) 4000 (c) 40
  24. 24.Best estimate of 643 + 383? (a) 800 (b) 1000 (c) 1200
  25. 25.Best estimate of 120 + 767? (a) 900 (b) 700 (c) 1100
  26. 26.Best estimate of 470 + 717? (a) 1000 (b) 1200 (c) 1400
  27. 27.Best estimate of 219 + 572? (a) 1000 (b) 800 (c) 600
  28. 28.Best estimate of 151 + 361? (a) 400 (b) 600 (c) 800
  29. 29.Best estimate of 396 + 798? (a) 1400 (b) 1000 (c) 1200
  30. 30.Best estimate of 203 + 643? (a) 1000 (b) 600 (c) 800
  31. 31.Best estimate of 264 + 699? (a) 1000 (b) 800 (c) 1200
  32. 32.Best estimate of 54 × 76? (a) 4000 (b) 40000 (c) 400
  33. 33.Best estimate of 295 + 342? (a) 600 (b) 400 (c) 800
  34. 34.Best estimate of 451 + 637? (a) 900 (b) 1300 (c) 1100
  35. 35.Best estimate of 24 × 34? (a) 600 (b) 6000 (c) 60
  36. 36.Best estimate of 16 × 96? (a) 20000 (b) 2000 (c) 200
  37. 37.Best estimate of 376 + 197? (a) 400 (b) 600 (c) 800
  38. 38.Best estimate of 18 × 36? (a) 800 (b) 80 (c) 8000
  39. 39.Best estimate of 126 + 609? (a) 900 (b) 500 (c) 700
  40. 40.Best estimate of 82 × 48? (a) 40000 (b) 400 (c) 4000

Answer key

  1. 900
  2. 600
  3. 2000
  4. 500
  5. 1200
  6. 5400
  7. 1100
  8. 1200
  9. 1400
  10. 800
  11. 9000
  12. 900
  13. 1500
  14. 900
  15. 3600
  16. 1500
  17. 800
  18. 800
  19. 800
  20. 3600
  21. 1000
  22. 3200
  23. 400
  24. 1000
  25. 900
  26. 1200
  27. 800
  28. 600
  29. 1200
  30. 800
  31. 1000
  32. 4000
  33. 600
  34. 1100
  35. 600
  36. 2000
  37. 600
  38. 800
  39. 700
  40. 4000

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