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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 807 · 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 94 × 36? (a) 360 (b) 36000 (c) 3600
  2. 2.Best estimate of 573 + 789? (a) 1600 (b) 1200 (c) 1400
  3. 3.Best estimate of 98 × 86? (a) 9000 (b) 900 (c) 90000
  4. 4.Best estimate of 701 + 662? (a) 1600 (b) 1400 (c) 1200
  5. 5.Best estimate of 314 + 488? (a) 600 (b) 800 (c) 1000
  6. 6.Best estimate of 126 + 518? (a) 400 (b) 800 (c) 600
  7. 7.Best estimate of 128 + 395? (a) 500 (b) 300 (c) 700
  8. 8.Best estimate of 717 + 560? (a) 1300 (b) 1100 (c) 1500
  9. 9.Best estimate of 64 × 50? (a) 3000 (b) 30000 (c) 300
  10. 10.Best estimate of 58 × 93? (a) 5400 (b) 540 (c) 54000
  11. 11.Best estimate of 31 × 87? (a) 2700 (b) 270 (c) 27000
  12. 12.Best estimate of 336 + 686? (a) 1200 (b) 800 (c) 1000
  13. 13.Best estimate of 483 + 536? (a) 800 (b) 1000 (c) 1200
  14. 14.Best estimate of 547 + 192? (a) 700 (b) 900 (c) 500
  15. 15.Best estimate of 22 × 67? (a) 14000 (b) 1400 (c) 140
  16. 16.Best estimate of 194 + 641? (a) 600 (b) 1000 (c) 800
  17. 17.Best estimate of 36 × 51? (a) 200 (b) 2000 (c) 20000
  18. 18.Best estimate of 768 + 143? (a) 900 (b) 700 (c) 1100
  19. 19.Best estimate of 296 + 594? (a) 700 (b) 900 (c) 1100
  20. 20.Best estimate of 388 + 367? (a) 600 (b) 800 (c) 1000
  21. 21.Best estimate of 641 + 663? (a) 1300 (b) 1500 (c) 1100
  22. 22.Best estimate of 866 + 276? (a) 1000 (b) 1400 (c) 1200
  23. 23.Best estimate of 67 × 94? (a) 63000 (b) 6300 (c) 630
  24. 24.Best estimate of 17 × 96? (a) 20000 (b) 200 (c) 2000
  25. 25.Best estimate of 87 × 32? (a) 2700 (b) 27000 (c) 270
  26. 26.Best estimate of 241 + 866? (a) 1100 (b) 1300 (c) 900
  27. 27.Best estimate of 429 + 173? (a) 400 (b) 800 (c) 600
  28. 28.Best estimate of 675 + 670? (a) 1200 (b) 1600 (c) 1400
  29. 29.Best estimate of 27 × 19? (a) 60 (b) 600 (c) 6000
  30. 30.Best estimate of 54 × 81? (a) 40000 (b) 4000 (c) 400
  31. 31.Best estimate of 300 + 657? (a) 800 (b) 1000 (c) 1200
  32. 32.Best estimate of 90 × 90? (a) 8100 (b) 810 (c) 81000
  33. 33.Best estimate of 12 × 16? (a) 20 (b) 200 (c) 2000
  34. 34.Best estimate of 865 + 344? (a) 1200 (b) 1000 (c) 1400
  35. 35.Best estimate of 22 × 21? (a) 4000 (b) 400 (c) 40
  36. 36.Best estimate of 28 × 89? (a) 27000 (b) 2700 (c) 270
  37. 37.Best estimate of 622 + 317? (a) 900 (b) 700 (c) 1100
  38. 38.Best estimate of 96 × 22? (a) 20000 (b) 200 (c) 2000
  39. 39.Best estimate of 37 × 69? (a) 280 (b) 2800 (c) 28000
  40. 40.Best estimate of 36 × 76? (a) 320 (b) 3200 (c) 32000

Answer key

  1. 3600
  2. 1400
  3. 9000
  4. 1400
  5. 800
  6. 600
  7. 500
  8. 1300
  9. 3000
  10. 5400
  11. 2700
  12. 1000
  13. 1000
  14. 700
  15. 1400
  16. 800
  17. 2000
  18. 900
  19. 900
  20. 800
  21. 1300
  22. 1200
  23. 6300
  24. 2000
  25. 2700
  26. 1100
  27. 600
  28. 1400
  29. 600
  30. 4000
  31. 1000
  32. 8100
  33. 200
  34. 1200
  35. 400
  36. 2700
  37. 900
  38. 2000
  39. 2800
  40. 3200

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