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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 617 · 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 76 × 96? (a) 800 (b) 80000 (c) 8000
  2. 2.Best estimate of 17 × 73? (a) 14000 (b) 1400 (c) 140
  3. 3.Best estimate of 156 + 213? (a) 400 (b) 600 (c) 200
  4. 4.Best estimate of 781 + 764? (a) 1800 (b) 1600 (c) 1400
  5. 5.Best estimate of 373 + 378? (a) 600 (b) 800 (c) 1000
  6. 6.Best estimate of 43 × 82? (a) 3200 (b) 320 (c) 32000
  7. 7.Best estimate of 833 + 183? (a) 1000 (b) 800 (c) 1200
  8. 8.Best estimate of 20 × 67? (a) 1400 (b) 140 (c) 14000
  9. 9.Best estimate of 19 × 54? (a) 10000 (b) 100 (c) 1000
  10. 10.Best estimate of 46 × 34? (a) 15000 (b) 150 (c) 1500
  11. 11.Best estimate of 468 + 692? (a) 1000 (b) 1200 (c) 1400
  12. 12.Best estimate of 662 + 168? (a) 700 (b) 900 (c) 1100
  13. 13.Best estimate of 90 × 71? (a) 6300 (b) 63000 (c) 630
  14. 14.Best estimate of 96 × 96? (a) 100000 (b) 10000 (c) 1000
  15. 15.Best estimate of 405 + 370? (a) 800 (b) 600 (c) 1000
  16. 16.Best estimate of 79 × 74? (a) 5600 (b) 560 (c) 56000
  17. 17.Best estimate of 96 × 61? (a) 60000 (b) 6000 (c) 600
  18. 18.Best estimate of 36 × 16? (a) 8000 (b) 80 (c) 800
  19. 19.Best estimate of 474 + 596? (a) 1300 (b) 1100 (c) 900
  20. 20.Best estimate of 540 + 810? (a) 1100 (b) 1300 (c) 1500
  21. 21.Best estimate of 357 + 232? (a) 600 (b) 400 (c) 800
  22. 22.Best estimate of 204 + 272? (a) 300 (b) 700 (c) 500
  23. 23.Best estimate of 91 × 33? (a) 2700 (b) 27000 (c) 270
  24. 24.Best estimate of 338 + 521? (a) 800 (b) 600 (c) 1000
  25. 25.Best estimate of 37 × 96? (a) 400 (b) 4000 (c) 40000
  26. 26.Best estimate of 64 × 38? (a) 24000 (b) 2400 (c) 240
  27. 27.Best estimate of 92 × 73? (a) 63000 (b) 6300 (c) 630
  28. 28.Best estimate of 839 + 472? (a) 1300 (b) 1100 (c) 1500
  29. 29.Best estimate of 48 × 23? (a) 10000 (b) 1000 (c) 100
  30. 30.Best estimate of 73 × 84? (a) 5600 (b) 56000 (c) 560
  31. 31.Best estimate of 772 + 708? (a) 1500 (b) 1700 (c) 1300
  32. 32.Best estimate of 57 × 53? (a) 300 (b) 30000 (c) 3000
  33. 33.Best estimate of 70 × 12? (a) 70 (b) 700 (c) 7000
  34. 34.Best estimate of 168 + 179? (a) 600 (b) 400 (c) 200
  35. 35.Best estimate of 214 + 331? (a) 500 (b) 700 (c) 300
  36. 36.Best estimate of 392 + 413? (a) 800 (b) 1000 (c) 600
  37. 37.Best estimate of 68 × 62? (a) 4200 (b) 42000 (c) 420
  38. 38.Best estimate of 88 × 43? (a) 3600 (b) 360 (c) 36000
  39. 39.Best estimate of 30 × 69? (a) 21000 (b) 2100 (c) 210
  40. 40.Best estimate of 86 × 62? (a) 5400 (b) 54000 (c) 540

Answer key

  1. 8000
  2. 1400
  3. 400
  4. 1600
  5. 800
  6. 3200
  7. 1000
  8. 1400
  9. 1000
  10. 1500
  11. 1200
  12. 900
  13. 6300
  14. 10000
  15. 800
  16. 5600
  17. 6000
  18. 800
  19. 1100
  20. 1300
  21. 600
  22. 500
  23. 2700
  24. 800
  25. 4000
  26. 2400
  27. 6300
  28. 1300
  29. 1000
  30. 5600
  31. 1500
  32. 3000
  33. 700
  34. 400
  35. 500
  36. 800
  37. 4200
  38. 3600
  39. 2100
  40. 5400

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