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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 25 · 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 31 × 17? (a) 600 (b) 6000 (c) 60
  2. 2.Best estimate of 46 × 56? (a) 300 (b) 3000 (c) 30000
  3. 3.Best estimate of 264 + 740? (a) 1000 (b) 1200 (c) 800
  4. 4.Best estimate of 50 × 62? (a) 3000 (b) 30000 (c) 300
  5. 5.Best estimate of 689 + 260? (a) 1200 (b) 1000 (c) 800
  6. 6.Best estimate of 773 + 205? (a) 1200 (b) 1000 (c) 800
  7. 7.Best estimate of 696 + 369? (a) 1300 (b) 1100 (c) 900
  8. 8.Best estimate of 177 + 603? (a) 1000 (b) 600 (c) 800
  9. 9.Best estimate of 94 × 88? (a) 8100 (b) 810 (c) 81000
  10. 10.Best estimate of 72 × 83? (a) 56000 (b) 5600 (c) 560
  11. 11.Best estimate of 783 + 198? (a) 1200 (b) 800 (c) 1000
  12. 12.Best estimate of 59 × 71? (a) 4200 (b) 420 (c) 42000
  13. 13.Best estimate of 38 × 41? (a) 1600 (b) 16000 (c) 160
  14. 14.Best estimate of 86 × 42? (a) 36000 (b) 360 (c) 3600
  15. 15.Best estimate of 725 + 721? (a) 1400 (b) 1600 (c) 1200
  16. 16.Best estimate of 357 + 474? (a) 900 (b) 700 (c) 1100
  17. 17.Best estimate of 56 × 66? (a) 4200 (b) 42000 (c) 420
  18. 18.Best estimate of 27 × 96? (a) 300 (b) 3000 (c) 30000
  19. 19.Best estimate of 66 × 26? (a) 21000 (b) 2100 (c) 210
  20. 20.Best estimate of 66 × 46? (a) 35000 (b) 350 (c) 3500
  21. 21.Best estimate of 260 + 769? (a) 900 (b) 1300 (c) 1100
  22. 22.Best estimate of 79 × 12? (a) 80 (b) 800 (c) 8000
  23. 23.Best estimate of 678 + 729? (a) 1200 (b) 1600 (c) 1400
  24. 24.Best estimate of 298 + 229? (a) 300 (b) 700 (c) 500
  25. 25.Best estimate of 92 × 74? (a) 63000 (b) 630 (c) 6300
  26. 26.Best estimate of 72 × 96? (a) 700 (b) 70000 (c) 7000
  27. 27.Best estimate of 786 + 591? (a) 1400 (b) 1600 (c) 1200
  28. 28.Best estimate of 855 + 842? (a) 1700 (b) 1500 (c) 1900
  29. 29.Best estimate of 163 + 814? (a) 1000 (b) 1200 (c) 800
  30. 30.Best estimate of 242 + 607? (a) 1000 (b) 600 (c) 800
  31. 31.Best estimate of 12 × 73? (a) 700 (b) 70 (c) 7000
  32. 32.Best estimate of 94 × 31? (a) 2700 (b) 27000 (c) 270
  33. 33.Best estimate of 58 × 14? (a) 600 (b) 60 (c) 6000
  34. 34.Best estimate of 58 × 37? (a) 240 (b) 24000 (c) 2400
  35. 35.Best estimate of 327 + 304? (a) 400 (b) 600 (c) 800
  36. 36.Best estimate of 78 × 27? (a) 2400 (b) 240 (c) 24000
  37. 37.Best estimate of 26 × 81? (a) 24000 (b) 240 (c) 2400
  38. 38.Best estimate of 76 × 22? (a) 160 (b) 1600 (c) 16000
  39. 39.Best estimate of 96 × 81? (a) 800 (b) 80000 (c) 8000
  40. 40.Best estimate of 17 × 18? (a) 400 (b) 4000 (c) 40

Answer key

  1. 600
  2. 3000
  3. 1000
  4. 3000
  5. 1000
  6. 1000
  7. 1100
  8. 800
  9. 8100
  10. 5600
  11. 1000
  12. 4200
  13. 1600
  14. 3600
  15. 1400
  16. 900
  17. 4200
  18. 3000
  19. 2100
  20. 3500
  21. 1100
  22. 800
  23. 1400
  24. 500
  25. 6300
  26. 7000
  27. 1400
  28. 1700
  29. 1000
  30. 800
  31. 700
  32. 2700
  33. 600
  34. 2400
  35. 600
  36. 2400
  37. 2400
  38. 1600
  39. 8000
  40. 400

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