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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 244 · 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 788 + 389? (a) 1000 (b) 1200 (c) 1400
  2. 2.Best estimate of 23 × 71? (a) 140 (b) 1400 (c) 14000
  3. 3.Best estimate of 691 + 143? (a) 800 (b) 1000 (c) 600
  4. 4.Best estimate of 22 × 17? (a) 4000 (b) 40 (c) 400
  5. 5.Best estimate of 76 × 93? (a) 7200 (b) 720 (c) 72000
  6. 6.Best estimate of 700 + 489? (a) 1400 (b) 1200 (c) 1000
  7. 7.Best estimate of 769 + 807? (a) 1800 (b) 1600 (c) 1400
  8. 8.Best estimate of 19 × 37? (a) 800 (b) 8000 (c) 80
  9. 9.Best estimate of 504 + 264? (a) 800 (b) 1000 (c) 600
  10. 10.Best estimate of 14 × 52? (a) 500 (b) 5000 (c) 50
  11. 11.Best estimate of 36 × 66? (a) 28000 (b) 2800 (c) 280
  12. 12.Best estimate of 63 × 82? (a) 48000 (b) 4800 (c) 480
  13. 13.Best estimate of 20 × 12? (a) 2000 (b) 20 (c) 200
  14. 14.Best estimate of 514 + 603? (a) 900 (b) 1100 (c) 1300
  15. 15.Best estimate of 91 × 22? (a) 1800 (b) 18000 (c) 180
  16. 16.Best estimate of 232 + 673? (a) 900 (b) 1100 (c) 700
  17. 17.Best estimate of 69 × 33? (a) 210 (b) 2100 (c) 21000
  18. 18.Best estimate of 738 + 688? (a) 1400 (b) 1600 (c) 1200
  19. 19.Best estimate of 33 × 87? (a) 27000 (b) 270 (c) 2700
  20. 20.Best estimate of 66 × 86? (a) 6300 (b) 630 (c) 63000
  21. 21.Best estimate of 225 + 819? (a) 1200 (b) 1000 (c) 800
  22. 22.Best estimate of 444 + 324? (a) 900 (b) 700 (c) 500
  23. 23.Best estimate of 524 + 814? (a) 1500 (b) 1100 (c) 1300
  24. 24.Best estimate of 96 × 72? (a) 7000 (b) 70000 (c) 700
  25. 25.Best estimate of 54 × 76? (a) 400 (b) 4000 (c) 40000
  26. 26.Best estimate of 84 × 50? (a) 40000 (b) 400 (c) 4000
  27. 27.Best estimate of 462 + 823? (a) 1300 (b) 1500 (c) 1100
  28. 28.Best estimate of 329 + 293? (a) 800 (b) 600 (c) 400
  29. 29.Best estimate of 389 + 774? (a) 1400 (b) 1000 (c) 1200
  30. 30.Best estimate of 222 + 316? (a) 700 (b) 500 (c) 300
  31. 31.Best estimate of 89 × 33? (a) 270 (b) 27000 (c) 2700
  32. 32.Best estimate of 858 + 858? (a) 1600 (b) 1800 (c) 2000
  33. 33.Best estimate of 63 × 98? (a) 600 (b) 60000 (c) 6000
  34. 34.Best estimate of 504 + 249? (a) 900 (b) 700 (c) 500
  35. 35.Best estimate of 634 + 574? (a) 1400 (b) 1200 (c) 1000
  36. 36.Best estimate of 426 + 867? (a) 1500 (b) 1300 (c) 1100
  37. 37.Best estimate of 381 + 220? (a) 400 (b) 600 (c) 800
  38. 38.Best estimate of 49 × 63? (a) 3000 (b) 300 (c) 30000
  39. 39.Best estimate of 338 + 320? (a) 400 (b) 600 (c) 800
  40. 40.Best estimate of 13 × 88? (a) 90 (b) 900 (c) 9000

Answer key

  1. 1200
  2. 1400
  3. 800
  4. 400
  5. 7200
  6. 1200
  7. 1600
  8. 800
  9. 800
  10. 500
  11. 2800
  12. 4800
  13. 200
  14. 1100
  15. 1800
  16. 900
  17. 2100
  18. 1400
  19. 2700
  20. 6300
  21. 1000
  22. 700
  23. 1300
  24. 7000
  25. 4000
  26. 4000
  27. 1300
  28. 600
  29. 1200
  30. 500
  31. 2700
  32. 1800
  33. 6000
  34. 700
  35. 1200
  36. 1300
  37. 600
  38. 3000
  39. 600
  40. 900

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