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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 297 · 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 719 + 523? (a) 1000 (b) 1200 (c) 1400
  2. 2.Best estimate of 64 × 92? (a) 540 (b) 54000 (c) 5400
  3. 3.Best estimate of 654 + 378? (a) 900 (b) 1100 (c) 1300
  4. 4.Best estimate of 346 + 791? (a) 1300 (b) 900 (c) 1100
  5. 5.Best estimate of 67 × 19? (a) 140 (b) 14000 (c) 1400
  6. 6.Best estimate of 79 × 39? (a) 320 (b) 32000 (c) 3200
  7. 7.Best estimate of 72 × 90? (a) 6300 (b) 630 (c) 63000
  8. 8.Best estimate of 50 × 41? (a) 2000 (b) 200 (c) 20000
  9. 9.Best estimate of 96 × 53? (a) 50000 (b) 5000 (c) 500
  10. 10.Best estimate of 46 × 98? (a) 5000 (b) 500 (c) 50000
  11. 11.Best estimate of 64 × 63? (a) 36000 (b) 360 (c) 3600
  12. 12.Best estimate of 16 × 41? (a) 800 (b) 80 (c) 8000
  13. 13.Best estimate of 21 × 32? (a) 60 (b) 6000 (c) 600
  14. 14.Best estimate of 82 × 59? (a) 4800 (b) 480 (c) 48000
  15. 15.Best estimate of 87 × 24? (a) 1800 (b) 180 (c) 18000
  16. 16.Best estimate of 206 + 823? (a) 1000 (b) 1200 (c) 800
  17. 17.Best estimate of 449 + 298? (a) 700 (b) 900 (c) 500
  18. 18.Best estimate of 33 × 89? (a) 27000 (b) 270 (c) 2700
  19. 19.Best estimate of 33 × 72? (a) 21000 (b) 2100 (c) 210
  20. 20.Best estimate of 727 + 825? (a) 1700 (b) 1500 (c) 1300
  21. 21.Best estimate of 781 + 573? (a) 1200 (b) 1600 (c) 1400
  22. 22.Best estimate of 78 × 86? (a) 72000 (b) 720 (c) 7200
  23. 23.Best estimate of 59 × 56? (a) 3600 (b) 36000 (c) 360
  24. 24.Best estimate of 82 × 16? (a) 1600 (b) 160 (c) 16000
  25. 25.Best estimate of 76 × 60? (a) 48000 (b) 4800 (c) 480
  26. 26.Best estimate of 831 + 836? (a) 1400 (b) 1800 (c) 1600
  27. 27.Best estimate of 47 × 60? (a) 3000 (b) 30000 (c) 300
  28. 28.Best estimate of 329 + 322? (a) 400 (b) 800 (c) 600
  29. 29.Best estimate of 38 × 33? (a) 12000 (b) 120 (c) 1200
  30. 30.Best estimate of 36 × 58? (a) 2400 (b) 24000 (c) 240
  31. 31.Best estimate of 800 + 298? (a) 1100 (b) 900 (c) 1300
  32. 32.Best estimate of 27 × 36? (a) 1200 (b) 120 (c) 12000
  33. 33.Best estimate of 16 × 18? (a) 4000 (b) 400 (c) 40
  34. 34.Best estimate of 569 + 529? (a) 1300 (b) 1100 (c) 900
  35. 35.Best estimate of 27 × 22? (a) 6000 (b) 600 (c) 60
  36. 36.Best estimate of 632 + 323? (a) 900 (b) 1100 (c) 700
  37. 37.Best estimate of 53 × 63? (a) 30000 (b) 300 (c) 3000
  38. 38.Best estimate of 26 × 83? (a) 2400 (b) 24000 (c) 240
  39. 39.Best estimate of 864 + 349? (a) 1000 (b) 1400 (c) 1200
  40. 40.Best estimate of 61 × 62? (a) 360 (b) 3600 (c) 36000

Answer key

  1. 1200
  2. 5400
  3. 1100
  4. 1100
  5. 1400
  6. 3200
  7. 6300
  8. 2000
  9. 5000
  10. 5000
  11. 3600
  12. 800
  13. 600
  14. 4800
  15. 1800
  16. 1000
  17. 700
  18. 2700
  19. 2100
  20. 1500
  21. 1400
  22. 7200
  23. 3600
  24. 1600
  25. 4800
  26. 1600
  27. 3000
  28. 600
  29. 1200
  30. 2400
  31. 1100
  32. 1200
  33. 400
  34. 1100
  35. 600
  36. 900
  37. 3000
  38. 2400
  39. 1200
  40. 3600

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