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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 383 · 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 460 + 313? (a) 600 (b) 1000 (c) 800
  2. 2.Best estimate of 58 × 19? (a) 12000 (b) 120 (c) 1200
  3. 3.Best estimate of 84 × 48? (a) 400 (b) 40000 (c) 4000
  4. 4.Best estimate of 89 × 13? (a) 900 (b) 9000 (c) 90
  5. 5.Best estimate of 46 × 27? (a) 150 (b) 15000 (c) 1500
  6. 6.Best estimate of 535 + 263? (a) 800 (b) 600 (c) 1000
  7. 7.Best estimate of 50 × 89? (a) 4500 (b) 45000 (c) 450
  8. 8.Best estimate of 196 + 487? (a) 900 (b) 700 (c) 500
  9. 9.Best estimate of 70 × 13? (a) 70 (b) 700 (c) 7000
  10. 10.Best estimate of 56 × 92? (a) 540 (b) 54000 (c) 5400
  11. 11.Best estimate of 566 + 752? (a) 1200 (b) 1600 (c) 1400
  12. 12.Best estimate of 81 × 74? (a) 56000 (b) 5600 (c) 560
  13. 13.Best estimate of 802 + 418? (a) 1400 (b) 1000 (c) 1200
  14. 14.Best estimate of 74 × 62? (a) 42000 (b) 420 (c) 4200
  15. 15.Best estimate of 29 × 23? (a) 6000 (b) 60 (c) 600
  16. 16.Best estimate of 499 + 211? (a) 700 (b) 500 (c) 900
  17. 17.Best estimate of 295 + 146? (a) 200 (b) 600 (c) 400
  18. 18.Best estimate of 36 × 94? (a) 360 (b) 3600 (c) 36000
  19. 19.Best estimate of 31 × 54? (a) 150 (b) 1500 (c) 15000
  20. 20.Best estimate of 718 + 315? (a) 1200 (b) 1000 (c) 800
  21. 21.Best estimate of 56 × 41? (a) 24000 (b) 2400 (c) 240
  22. 22.Best estimate of 830 + 406? (a) 1400 (b) 1200 (c) 1000
  23. 23.Best estimate of 17 × 53? (a) 100 (b) 1000 (c) 10000
  24. 24.Best estimate of 76 × 96? (a) 800 (b) 8000 (c) 80000
  25. 25.Best estimate of 636 + 728? (a) 1300 (b) 1100 (c) 1500
  26. 26.Best estimate of 27 × 31? (a) 9000 (b) 90 (c) 900
  27. 27.Best estimate of 800 + 220? (a) 1000 (b) 800 (c) 1200
  28. 28.Best estimate of 120 + 242? (a) 100 (b) 500 (c) 300
  29. 29.Best estimate of 788 + 265? (a) 1100 (b) 1300 (c) 900
  30. 30.Best estimate of 686 + 523? (a) 1400 (b) 1000 (c) 1200
  31. 31.Best estimate of 57 × 63? (a) 360 (b) 36000 (c) 3600
  32. 32.Best estimate of 54 × 26? (a) 1500 (b) 15000 (c) 150
  33. 33.Best estimate of 90 × 36? (a) 36000 (b) 3600 (c) 360
  34. 34.Best estimate of 19 × 88? (a) 180 (b) 18000 (c) 1800
  35. 35.Best estimate of 270 + 178? (a) 500 (b) 700 (c) 300
  36. 36.Best estimate of 31 × 69? (a) 2100 (b) 210 (c) 21000
  37. 37.Best estimate of 873 + 632? (a) 1500 (b) 1300 (c) 1700
  38. 38.Best estimate of 354 + 392? (a) 600 (b) 1000 (c) 800
  39. 39.Best estimate of 432 + 239? (a) 600 (b) 800 (c) 400
  40. 40.Best estimate of 284 + 466? (a) 800 (b) 1000 (c) 600

Answer key

  1. 800
  2. 1200
  3. 4000
  4. 900
  5. 1500
  6. 800
  7. 4500
  8. 700
  9. 700
  10. 5400
  11. 1400
  12. 5600
  13. 1200
  14. 4200
  15. 600
  16. 700
  17. 400
  18. 3600
  19. 1500
  20. 1000
  21. 2400
  22. 1200
  23. 1000
  24. 8000
  25. 1300
  26. 900
  27. 1000
  28. 300
  29. 1100
  30. 1200
  31. 3600
  32. 1500
  33. 3600
  34. 1800
  35. 500
  36. 2100
  37. 1500
  38. 800
  39. 600
  40. 800

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