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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 733 · 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 312 + 803? (a) 1300 (b) 1100 (c) 900
  2. 2.Best estimate of 29 × 97? (a) 30000 (b) 3000 (c) 300
  3. 3.Best estimate of 168 + 249? (a) 200 (b) 600 (c) 400
  4. 4.Best estimate of 706 + 449? (a) 1300 (b) 900 (c) 1100
  5. 5.Best estimate of 184 + 369? (a) 600 (b) 800 (c) 400
  6. 6.Best estimate of 685 + 275? (a) 1000 (b) 1200 (c) 800
  7. 7.Best estimate of 874 + 852? (a) 2000 (b) 1600 (c) 1800
  8. 8.Best estimate of 86 × 46? (a) 45000 (b) 450 (c) 4500
  9. 9.Best estimate of 393 + 573? (a) 1200 (b) 800 (c) 1000
  10. 10.Best estimate of 44 × 24? (a) 800 (b) 80 (c) 8000
  11. 11.Best estimate of 568 + 551? (a) 1400 (b) 1000 (c) 1200
  12. 12.Best estimate of 49 × 42? (a) 2000 (b) 20000 (c) 200
  13. 13.Best estimate of 824 + 594? (a) 1600 (b) 1400 (c) 1200
  14. 14.Best estimate of 263 + 582? (a) 900 (b) 700 (c) 1100
  15. 15.Best estimate of 875 + 241? (a) 1300 (b) 900 (c) 1100
  16. 16.Best estimate of 76 × 54? (a) 4000 (b) 400 (c) 40000
  17. 17.Best estimate of 98 × 56? (a) 600 (b) 6000 (c) 60000
  18. 18.Best estimate of 672 + 839? (a) 1300 (b) 1700 (c) 1500
  19. 19.Best estimate of 776 + 446? (a) 1200 (b) 1400 (c) 1000
  20. 20.Best estimate of 625 + 239? (a) 1000 (b) 600 (c) 800
  21. 21.Best estimate of 80 × 69? (a) 5600 (b) 560 (c) 56000
  22. 22.Best estimate of 614 + 138? (a) 900 (b) 500 (c) 700
  23. 23.Best estimate of 28 × 81? (a) 2400 (b) 240 (c) 24000
  24. 24.Best estimate of 564 + 143? (a) 700 (b) 500 (c) 900
  25. 25.Best estimate of 190 + 641? (a) 1000 (b) 800 (c) 600
  26. 26.Best estimate of 744 + 519? (a) 1000 (b) 1400 (c) 1200
  27. 27.Best estimate of 61 × 29? (a) 1800 (b) 180 (c) 18000
  28. 28.Best estimate of 24 × 34? (a) 6000 (b) 60 (c) 600
  29. 29.Best estimate of 51 × 66? (a) 350 (b) 35000 (c) 3500
  30. 30.Best estimate of 156 + 214? (a) 200 (b) 400 (c) 600
  31. 31.Best estimate of 60 × 66? (a) 42000 (b) 420 (c) 4200
  32. 32.Best estimate of 683 + 489? (a) 1200 (b) 1400 (c) 1000
  33. 33.Best estimate of 22 × 76? (a) 16000 (b) 160 (c) 1600
  34. 34.Best estimate of 545 + 302? (a) 600 (b) 1000 (c) 800
  35. 35.Best estimate of 63 × 18? (a) 120 (b) 1200 (c) 12000
  36. 36.Best estimate of 26 × 27? (a) 90 (b) 900 (c) 9000
  37. 37.Best estimate of 12 × 76? (a) 8000 (b) 800 (c) 80
  38. 38.Best estimate of 715 + 656? (a) 1200 (b) 1400 (c) 1600
  39. 39.Best estimate of 419 + 751? (a) 1000 (b) 1400 (c) 1200
  40. 40.Best estimate of 524 + 608? (a) 1100 (b) 1300 (c) 900

Answer key

  1. 1100
  2. 3000
  3. 400
  4. 1100
  5. 600
  6. 1000
  7. 1800
  8. 4500
  9. 1000
  10. 800
  11. 1200
  12. 2000
  13. 1400
  14. 900
  15. 1100
  16. 4000
  17. 6000
  18. 1500
  19. 1200
  20. 800
  21. 5600
  22. 700
  23. 2400
  24. 700
  25. 800
  26. 1200
  27. 1800
  28. 600
  29. 3500
  30. 400
  31. 4200
  32. 1200
  33. 1600
  34. 800
  35. 1200
  36. 900
  37. 800
  38. 1400
  39. 1200
  40. 1100

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