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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 556 · 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 826 + 158? (a) 1000 (b) 1200 (c) 800
  2. 2.Best estimate of 62 × 34? (a) 180 (b) 1800 (c) 18000
  3. 3.Best estimate of 692 + 259? (a) 1200 (b) 1000 (c) 800
  4. 4.Best estimate of 46 × 21? (a) 100 (b) 10000 (c) 1000
  5. 5.Best estimate of 86 × 83? (a) 720 (b) 7200 (c) 72000
  6. 6.Best estimate of 34 × 81? (a) 2400 (b) 240 (c) 24000
  7. 7.Best estimate of 41 × 23? (a) 8000 (b) 80 (c) 800
  8. 8.Best estimate of 465 + 546? (a) 1200 (b) 800 (c) 1000
  9. 9.Best estimate of 62 × 52? (a) 30000 (b) 3000 (c) 300
  10. 10.Best estimate of 639 + 567? (a) 1200 (b) 1000 (c) 1400
  11. 11.Best estimate of 69 × 76? (a) 560 (b) 5600 (c) 56000
  12. 12.Best estimate of 83 × 22? (a) 16000 (b) 1600 (c) 160
  13. 13.Best estimate of 243 + 194? (a) 600 (b) 400 (c) 200
  14. 14.Best estimate of 592 + 876? (a) 1500 (b) 1300 (c) 1700
  15. 15.Best estimate of 479 + 673? (a) 1400 (b) 1200 (c) 1000
  16. 16.Best estimate of 17 × 21? (a) 4000 (b) 40 (c) 400
  17. 17.Best estimate of 43 × 16? (a) 8000 (b) 80 (c) 800
  18. 18.Best estimate of 70 × 67? (a) 490 (b) 4900 (c) 49000
  19. 19.Best estimate of 66 × 46? (a) 3500 (b) 35000 (c) 350
  20. 20.Best estimate of 30 × 20? (a) 600 (b) 6000 (c) 60
  21. 21.Best estimate of 47 × 32? (a) 1500 (b) 150 (c) 15000
  22. 22.Best estimate of 69 × 33? (a) 210 (b) 2100 (c) 21000
  23. 23.Best estimate of 73 × 82? (a) 5600 (b) 56000 (c) 560
  24. 24.Best estimate of 44 × 32? (a) 120 (b) 1200 (c) 12000
  25. 25.Best estimate of 17 × 38? (a) 800 (b) 8000 (c) 80
  26. 26.Best estimate of 82 × 28? (a) 2400 (b) 240 (c) 24000
  27. 27.Best estimate of 14 × 96? (a) 10000 (b) 100 (c) 1000
  28. 28.Best estimate of 832 + 610? (a) 1200 (b) 1600 (c) 1400
  29. 29.Best estimate of 98 × 69? (a) 70000 (b) 700 (c) 7000
  30. 30.Best estimate of 315 + 314? (a) 800 (b) 400 (c) 600
  31. 31.Best estimate of 49 × 41? (a) 200 (b) 20000 (c) 2000
  32. 32.Best estimate of 76 × 51? (a) 4000 (b) 400 (c) 40000
  33. 33.Best estimate of 91 × 56? (a) 5400 (b) 54000 (c) 540
  34. 34.Best estimate of 839 + 378? (a) 1200 (b) 1400 (c) 1000
  35. 35.Best estimate of 835 + 878? (a) 1900 (b) 1500 (c) 1700
  36. 36.Best estimate of 755 + 792? (a) 1800 (b) 1600 (c) 1400
  37. 37.Best estimate of 797 + 762? (a) 1600 (b) 1800 (c) 1400
  38. 38.Best estimate of 513 + 697? (a) 1200 (b) 1400 (c) 1000
  39. 39.Best estimate of 64 × 58? (a) 3600 (b) 36000 (c) 360
  40. 40.Best estimate of 31 × 12? (a) 30 (b) 3000 (c) 300

Answer key

  1. 1000
  2. 1800
  3. 1000
  4. 1000
  5. 7200
  6. 2400
  7. 800
  8. 1000
  9. 3000
  10. 1200
  11. 5600
  12. 1600
  13. 400
  14. 1500
  15. 1200
  16. 400
  17. 800
  18. 4900
  19. 3500
  20. 600
  21. 1500
  22. 2100
  23. 5600
  24. 1200
  25. 800
  26. 2400
  27. 1000
  28. 1400
  29. 7000
  30. 600
  31. 2000
  32. 4000
  33. 5400
  34. 1200
  35. 1700
  36. 1600
  37. 1600
  38. 1200
  39. 3600
  40. 300

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