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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 442 · 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 216 + 872? (a) 1100 (b) 900 (c) 1300
  2. 2.Best estimate of 754 + 292? (a) 1300 (b) 1100 (c) 900
  3. 3.Best estimate of 58 × 61? (a) 360 (b) 36000 (c) 3600
  4. 4.Best estimate of 447 + 814? (a) 1400 (b) 1000 (c) 1200
  5. 5.Best estimate of 16 × 92? (a) 1800 (b) 18000 (c) 180
  6. 6.Best estimate of 16 × 32? (a) 600 (b) 6000 (c) 60
  7. 7.Best estimate of 621 + 449? (a) 1000 (b) 1200 (c) 800
  8. 8.Best estimate of 173 + 738? (a) 900 (b) 700 (c) 1100
  9. 9.Best estimate of 597 + 209? (a) 800 (b) 1000 (c) 600
  10. 10.Best estimate of 853 + 649? (a) 1700 (b) 1300 (c) 1500
  11. 11.Best estimate of 13 × 92? (a) 9000 (b) 900 (c) 90
  12. 12.Best estimate of 76 × 16? (a) 16000 (b) 160 (c) 1600
  13. 13.Best estimate of 584 + 120? (a) 700 (b) 500 (c) 900
  14. 14.Best estimate of 298 + 855? (a) 1000 (b) 1400 (c) 1200
  15. 15.Best estimate of 787 + 600? (a) 1400 (b) 1600 (c) 1200
  16. 16.Best estimate of 71 × 94? (a) 630 (b) 6300 (c) 63000
  17. 17.Best estimate of 34 × 68? (a) 21000 (b) 210 (c) 2100
  18. 18.Best estimate of 56 × 77? (a) 480 (b) 48000 (c) 4800
  19. 19.Best estimate of 64 × 60? (a) 3600 (b) 36000 (c) 360
  20. 20.Best estimate of 30 × 57? (a) 1800 (b) 18000 (c) 180
  21. 21.Best estimate of 28 × 79? (a) 2400 (b) 240 (c) 24000
  22. 22.Best estimate of 325 + 368? (a) 700 (b) 900 (c) 500
  23. 23.Best estimate of 358 + 515? (a) 700 (b) 900 (c) 1100
  24. 24.Best estimate of 494 + 641? (a) 1100 (b) 1300 (c) 900
  25. 25.Best estimate of 744 + 785? (a) 1700 (b) 1300 (c) 1500
  26. 26.Best estimate of 493 + 531? (a) 1000 (b) 800 (c) 1200
  27. 27.Best estimate of 76 × 94? (a) 72000 (b) 720 (c) 7200
  28. 28.Best estimate of 792 + 442? (a) 1000 (b) 1200 (c) 1400
  29. 29.Best estimate of 675 + 452? (a) 1400 (b) 1000 (c) 1200
  30. 30.Best estimate of 398 + 265? (a) 900 (b) 700 (c) 500
  31. 31.Best estimate of 789 + 870? (a) 1900 (b) 1500 (c) 1700
  32. 32.Best estimate of 79 × 29? (a) 2400 (b) 24000 (c) 240
  33. 33.Best estimate of 63 × 89? (a) 540 (b) 5400 (c) 54000
  34. 34.Best estimate of 859 + 535? (a) 1400 (b) 1600 (c) 1200
  35. 35.Best estimate of 223 + 663? (a) 700 (b) 1100 (c) 900
  36. 36.Best estimate of 59 × 18? (a) 120 (b) 1200 (c) 12000
  37. 37.Best estimate of 605 + 248? (a) 1000 (b) 800 (c) 600
  38. 38.Best estimate of 156 + 599? (a) 600 (b) 1000 (c) 800
  39. 39.Best estimate of 57 × 36? (a) 2400 (b) 240 (c) 24000
  40. 40.Best estimate of 510 + 787? (a) 1300 (b) 1100 (c) 1500

Answer key

  1. 1100
  2. 1100
  3. 3600
  4. 1200
  5. 1800
  6. 600
  7. 1000
  8. 900
  9. 800
  10. 1500
  11. 900
  12. 1600
  13. 700
  14. 1200
  15. 1400
  16. 6300
  17. 2100
  18. 4800
  19. 3600
  20. 1800
  21. 2400
  22. 700
  23. 900
  24. 1100
  25. 1500
  26. 1000
  27. 7200
  28. 1200
  29. 1200
  30. 700
  31. 1700
  32. 2400
  33. 5400
  34. 1400
  35. 900
  36. 1200
  37. 800
  38. 800
  39. 2400
  40. 1300

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