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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 695 · 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 88 × 30? (a) 27000 (b) 270 (c) 2700
  2. 2.Best estimate of 232 + 818? (a) 1200 (b) 800 (c) 1000
  3. 3.Best estimate of 278 + 361? (a) 900 (b) 500 (c) 700
  4. 4.Best estimate of 67 × 56? (a) 4200 (b) 42000 (c) 420
  5. 5.Best estimate of 782 + 300? (a) 1300 (b) 1100 (c) 900
  6. 6.Best estimate of 449 + 590? (a) 1200 (b) 800 (c) 1000
  7. 7.Best estimate of 83 × 86? (a) 7200 (b) 720 (c) 72000
  8. 8.Best estimate of 356 + 583? (a) 800 (b) 1000 (c) 1200
  9. 9.Best estimate of 36 × 78? (a) 3200 (b) 32000 (c) 320
  10. 10.Best estimate of 83 × 46? (a) 40000 (b) 400 (c) 4000
  11. 11.Best estimate of 71 × 26? (a) 210 (b) 2100 (c) 21000
  12. 12.Best estimate of 684 + 383? (a) 900 (b) 1300 (c) 1100
  13. 13.Best estimate of 866 + 793? (a) 1500 (b) 1700 (c) 1900
  14. 14.Best estimate of 74 × 50? (a) 350 (b) 35000 (c) 3500
  15. 15.Best estimate of 428 + 533? (a) 900 (b) 700 (c) 1100
  16. 16.Best estimate of 656 + 406? (a) 1100 (b) 900 (c) 1300
  17. 17.Best estimate of 93 × 92? (a) 8100 (b) 81000 (c) 810
  18. 18.Best estimate of 24 × 58? (a) 120 (b) 1200 (c) 12000
  19. 19.Best estimate of 166 + 337? (a) 500 (b) 700 (c) 300
  20. 20.Best estimate of 483 + 708? (a) 1200 (b) 1000 (c) 1400
  21. 21.Best estimate of 281 + 195? (a) 300 (b) 700 (c) 500
  22. 22.Best estimate of 206 + 516? (a) 900 (b) 500 (c) 700
  23. 23.Best estimate of 209 + 792? (a) 800 (b) 1000 (c) 1200
  24. 24.Best estimate of 22 × 58? (a) 12000 (b) 1200 (c) 120
  25. 25.Best estimate of 26 × 56? (a) 1800 (b) 180 (c) 18000
  26. 26.Best estimate of 30 × 82? (a) 240 (b) 2400 (c) 24000
  27. 27.Best estimate of 194 + 327? (a) 700 (b) 300 (c) 500
  28. 28.Best estimate of 16 × 66? (a) 14000 (b) 1400 (c) 140
  29. 29.Best estimate of 67 × 74? (a) 49000 (b) 4900 (c) 490
  30. 30.Best estimate of 361 + 329? (a) 500 (b) 700 (c) 900
  31. 31.Best estimate of 48 × 31? (a) 1500 (b) 150 (c) 15000
  32. 32.Best estimate of 81 × 41? (a) 320 (b) 32000 (c) 3200
  33. 33.Best estimate of 424 + 279? (a) 700 (b) 900 (c) 500
  34. 34.Best estimate of 81 × 39? (a) 32000 (b) 3200 (c) 320
  35. 35.Best estimate of 42 × 59? (a) 240 (b) 24000 (c) 2400
  36. 36.Best estimate of 193 + 597? (a) 600 (b) 800 (c) 1000
  37. 37.Best estimate of 765 + 731? (a) 1700 (b) 1300 (c) 1500
  38. 38.Best estimate of 56 × 68? (a) 42000 (b) 420 (c) 4200
  39. 39.Best estimate of 62 × 86? (a) 5400 (b) 540 (c) 54000
  40. 40.Best estimate of 474 + 430? (a) 900 (b) 1100 (c) 700

Answer key

  1. 2700
  2. 1000
  3. 700
  4. 4200
  5. 1100
  6. 1000
  7. 7200
  8. 1000
  9. 3200
  10. 4000
  11. 2100
  12. 1100
  13. 1700
  14. 3500
  15. 900
  16. 1100
  17. 8100
  18. 1200
  19. 500
  20. 1200
  21. 500
  22. 700
  23. 1000
  24. 1200
  25. 1800
  26. 2400
  27. 500
  28. 1400
  29. 4900
  30. 700
  31. 1500
  32. 3200
  33. 700
  34. 3200
  35. 2400
  36. 800
  37. 1500
  38. 4200
  39. 5400
  40. 900

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