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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 37 · 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 67 × 37? (a) 2800 (b) 280 (c) 28000
  2. 2.Best estimate of 787 + 230? (a) 800 (b) 1200 (c) 1000
  3. 3.Best estimate of 96 × 72? (a) 7000 (b) 700 (c) 70000
  4. 4.Best estimate of 690 + 382? (a) 900 (b) 1300 (c) 1100
  5. 5.Best estimate of 825 + 639? (a) 1200 (b) 1400 (c) 1600
  6. 6.Best estimate of 71 × 37? (a) 28000 (b) 2800 (c) 280
  7. 7.Best estimate of 87 × 13? (a) 9000 (b) 900 (c) 90
  8. 8.Best estimate of 61 × 86? (a) 540 (b) 5400 (c) 54000
  9. 9.Best estimate of 800 + 735? (a) 1500 (b) 1700 (c) 1300
  10. 10.Best estimate of 60 × 74? (a) 4200 (b) 420 (c) 42000
  11. 11.Best estimate of 149 + 824? (a) 1100 (b) 700 (c) 900
  12. 12.Best estimate of 91 × 98? (a) 900 (b) 9000 (c) 90000
  13. 13.Best estimate of 73 × 26? (a) 21000 (b) 2100 (c) 210
  14. 14.Best estimate of 124 + 880? (a) 800 (b) 1000 (c) 1200
  15. 15.Best estimate of 94 × 66? (a) 63000 (b) 6300 (c) 630
  16. 16.Best estimate of 694 + 557? (a) 1100 (b) 1500 (c) 1300
  17. 17.Best estimate of 94 × 63? (a) 5400 (b) 540 (c) 54000
  18. 18.Best estimate of 97 × 74? (a) 7000 (b) 70000 (c) 700
  19. 19.Best estimate of 48 × 43? (a) 2000 (b) 200 (c) 20000
  20. 20.Best estimate of 470 + 197? (a) 700 (b) 900 (c) 500
  21. 21.Best estimate of 271 + 621? (a) 900 (b) 1100 (c) 700
  22. 22.Best estimate of 20 × 32? (a) 60 (b) 600 (c) 6000
  23. 23.Best estimate of 469 + 781? (a) 1300 (b) 1100 (c) 1500
  24. 24.Best estimate of 29 × 36? (a) 12000 (b) 120 (c) 1200
  25. 25.Best estimate of 277 + 217? (a) 500 (b) 700 (c) 300
  26. 26.Best estimate of 46 × 71? (a) 350 (b) 3500 (c) 35000
  27. 27.Best estimate of 144 + 466? (a) 600 (b) 400 (c) 800
  28. 28.Best estimate of 746 + 424? (a) 900 (b) 1100 (c) 1300
  29. 29.Best estimate of 31 × 17? (a) 600 (b) 60 (c) 6000
  30. 30.Best estimate of 68 × 94? (a) 63000 (b) 630 (c) 6300
  31. 31.Best estimate of 22 × 37? (a) 80 (b) 800 (c) 8000
  32. 32.Best estimate of 763 + 539? (a) 1500 (b) 1300 (c) 1100
  33. 33.Best estimate of 555 + 681? (a) 1500 (b) 1300 (c) 1100
  34. 34.Best estimate of 81 × 40? (a) 32000 (b) 3200 (c) 320
  35. 35.Best estimate of 626 + 412? (a) 800 (b) 1000 (c) 1200
  36. 36.Best estimate of 21 × 16? (a) 400 (b) 40 (c) 4000
  37. 37.Best estimate of 151 + 712? (a) 900 (b) 1100 (c) 700
  38. 38.Best estimate of 40 × 61? (a) 240 (b) 24000 (c) 2400
  39. 39.Best estimate of 466 + 453? (a) 1000 (b) 1200 (c) 800
  40. 40.Best estimate of 858 + 572? (a) 1500 (b) 1300 (c) 1700

Answer key

  1. 2800
  2. 1000
  3. 7000
  4. 1100
  5. 1400
  6. 2800
  7. 900
  8. 5400
  9. 1500
  10. 4200
  11. 900
  12. 9000
  13. 2100
  14. 1000
  15. 6300
  16. 1300
  17. 5400
  18. 7000
  19. 2000
  20. 700
  21. 900
  22. 600
  23. 1300
  24. 1200
  25. 500
  26. 3500
  27. 600
  28. 1100
  29. 600
  30. 6300
  31. 800
  32. 1300
  33. 1300
  34. 3200
  35. 1000
  36. 400
  37. 900
  38. 2400
  39. 1000
  40. 1500

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