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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 589 · 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 317 + 619? (a) 1100 (b) 900 (c) 700
  2. 2.Best estimate of 92 × 56? (a) 5400 (b) 540 (c) 54000
  3. 3.Best estimate of 98 × 96? (a) 10000 (b) 1000 (c) 100000
  4. 4.Best estimate of 216 + 544? (a) 700 (b) 900 (c) 500
  5. 5.Best estimate of 822 + 871? (a) 1500 (b) 1900 (c) 1700
  6. 6.Best estimate of 122 + 195? (a) 500 (b) 100 (c) 300
  7. 7.Best estimate of 801 + 604? (a) 1600 (b) 1200 (c) 1400
  8. 8.Best estimate of 164 + 122? (a) 500 (b) 300 (c) 100
  9. 9.Best estimate of 264 + 628? (a) 1100 (b) 700 (c) 900
  10. 10.Best estimate of 83 × 73? (a) 56000 (b) 5600 (c) 560
  11. 11.Best estimate of 435 + 829? (a) 1200 (b) 1400 (c) 1000
  12. 12.Best estimate of 39 × 63? (a) 240 (b) 24000 (c) 2400
  13. 13.Best estimate of 286 + 232? (a) 700 (b) 500 (c) 300
  14. 14.Best estimate of 741 + 421? (a) 1100 (b) 1300 (c) 900
  15. 15.Best estimate of 858 + 233? (a) 1100 (b) 1300 (c) 900
  16. 16.Best estimate of 235 + 772? (a) 800 (b) 1200 (c) 1000
  17. 17.Best estimate of 90 × 82? (a) 720 (b) 72000 (c) 7200
  18. 18.Best estimate of 94 × 98? (a) 900 (b) 90000 (c) 9000
  19. 19.Best estimate of 84 × 70? (a) 5600 (b) 56000 (c) 560
  20. 20.Best estimate of 56 × 93? (a) 540 (b) 5400 (c) 54000
  21. 21.Best estimate of 16 × 70? (a) 14000 (b) 1400 (c) 140
  22. 22.Best estimate of 337 + 739? (a) 1000 (b) 800 (c) 1200
  23. 23.Best estimate of 831 + 559? (a) 1600 (b) 1200 (c) 1400
  24. 24.Best estimate of 426 + 569? (a) 1200 (b) 800 (c) 1000
  25. 25.Best estimate of 59 × 12? (a) 6000 (b) 600 (c) 60
  26. 26.Best estimate of 16 × 23? (a) 4000 (b) 400 (c) 40
  27. 27.Best estimate of 56 × 30? (a) 18000 (b) 180 (c) 1800
  28. 28.Best estimate of 58 × 30? (a) 180 (b) 1800 (c) 18000
  29. 29.Best estimate of 624 + 752? (a) 1200 (b) 1600 (c) 1400
  30. 30.Best estimate of 96 × 41? (a) 400 (b) 40000 (c) 4000
  31. 31.Best estimate of 530 + 829? (a) 1500 (b) 1300 (c) 1100
  32. 32.Best estimate of 523 + 305? (a) 1000 (b) 600 (c) 800
  33. 33.Best estimate of 588 + 392? (a) 800 (b) 1000 (c) 1200
  34. 34.Best estimate of 16 × 22? (a) 400 (b) 4000 (c) 40
  35. 35.Best estimate of 20 × 31? (a) 6000 (b) 60 (c) 600
  36. 36.Best estimate of 449 + 869? (a) 1300 (b) 1500 (c) 1100
  37. 37.Best estimate of 560 + 651? (a) 1500 (b) 1300 (c) 1100
  38. 38.Best estimate of 26 × 16? (a) 60 (b) 600 (c) 6000
  39. 39.Best estimate of 356 + 754? (a) 1400 (b) 1200 (c) 1000
  40. 40.Best estimate of 90 × 23? (a) 1800 (b) 180 (c) 18000

Answer key

  1. 900
  2. 5400
  3. 10000
  4. 700
  5. 1700
  6. 300
  7. 1400
  8. 300
  9. 900
  10. 5600
  11. 1200
  12. 2400
  13. 500
  14. 1100
  15. 1100
  16. 1000
  17. 7200
  18. 9000
  19. 5600
  20. 5400
  21. 1400
  22. 1000
  23. 1400
  24. 1000
  25. 600
  26. 400
  27. 1800
  28. 1800
  29. 1400
  30. 4000
  31. 1300
  32. 800
  33. 1000
  34. 400
  35. 600
  36. 1300
  37. 1300
  38. 600
  39. 1200
  40. 1800

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