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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 337 · 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 535 + 279? (a) 600 (b) 1000 (c) 800
  2. 2.Best estimate of 352 + 339? (a) 500 (b) 900 (c) 700
  3. 3.Best estimate of 59 × 44? (a) 240 (b) 2400 (c) 24000
  4. 4.Best estimate of 48 × 56? (a) 300 (b) 3000 (c) 30000
  5. 5.Best estimate of 12 × 29? (a) 30 (b) 300 (c) 3000
  6. 6.Best estimate of 785 + 688? (a) 1300 (b) 1700 (c) 1500
  7. 7.Best estimate of 21 × 48? (a) 1000 (b) 100 (c) 10000
  8. 8.Best estimate of 62 × 67? (a) 42000 (b) 4200 (c) 420
  9. 9.Best estimate of 89 × 56? (a) 540 (b) 5400 (c) 54000
  10. 10.Best estimate of 59 × 84? (a) 48000 (b) 480 (c) 4800
  11. 11.Best estimate of 502 + 653? (a) 1000 (b) 1200 (c) 1400
  12. 12.Best estimate of 24 × 80? (a) 1600 (b) 16000 (c) 160
  13. 13.Best estimate of 72 × 66? (a) 490 (b) 49000 (c) 4900
  14. 14.Best estimate of 50 × 60? (a) 30000 (b) 300 (c) 3000
  15. 15.Best estimate of 34 × 19? (a) 6000 (b) 60 (c) 600
  16. 16.Best estimate of 40 × 91? (a) 3600 (b) 360 (c) 36000
  17. 17.Best estimate of 38 × 29? (a) 12000 (b) 120 (c) 1200
  18. 18.Best estimate of 417 + 831? (a) 1400 (b) 1000 (c) 1200
  19. 19.Best estimate of 38 × 26? (a) 120 (b) 1200 (c) 12000
  20. 20.Best estimate of 88 × 84? (a) 7200 (b) 720 (c) 72000
  21. 21.Best estimate of 19 × 32? (a) 600 (b) 6000 (c) 60
  22. 22.Best estimate of 86 × 14? (a) 90 (b) 900 (c) 9000
  23. 23.Best estimate of 871 + 527? (a) 1600 (b) 1400 (c) 1200
  24. 24.Best estimate of 34 × 18? (a) 6000 (b) 60 (c) 600
  25. 25.Best estimate of 82 × 43? (a) 3200 (b) 32000 (c) 320
  26. 26.Best estimate of 484 + 638? (a) 1100 (b) 900 (c) 1300
  27. 27.Best estimate of 384 + 783? (a) 1200 (b) 1000 (c) 1400
  28. 28.Best estimate of 12 × 96? (a) 100 (b) 10000 (c) 1000
  29. 29.Best estimate of 51 × 23? (a) 100 (b) 10000 (c) 1000
  30. 30.Best estimate of 91 × 88? (a) 810 (b) 8100 (c) 81000
  31. 31.Best estimate of 261 + 570? (a) 900 (b) 700 (c) 1100
  32. 32.Best estimate of 67 × 21? (a) 14000 (b) 1400 (c) 140
  33. 33.Best estimate of 793 + 486? (a) 1300 (b) 1100 (c) 1500
  34. 34.Best estimate of 52 × 28? (a) 150 (b) 15000 (c) 1500
  35. 35.Best estimate of 414 + 385? (a) 600 (b) 800 (c) 1000
  36. 36.Best estimate of 66 × 51? (a) 3500 (b) 35000 (c) 350
  37. 37.Best estimate of 304 + 577? (a) 700 (b) 900 (c) 1100
  38. 38.Best estimate of 712 + 673? (a) 1200 (b) 1600 (c) 1400
  39. 39.Best estimate of 741 + 498? (a) 1400 (b) 1000 (c) 1200
  40. 40.Best estimate of 16 × 40? (a) 800 (b) 80 (c) 8000

Answer key

  1. 800
  2. 700
  3. 2400
  4. 3000
  5. 300
  6. 1500
  7. 1000
  8. 4200
  9. 5400
  10. 4800
  11. 1200
  12. 1600
  13. 4900
  14. 3000
  15. 600
  16. 3600
  17. 1200
  18. 1200
  19. 1200
  20. 7200
  21. 600
  22. 900
  23. 1400
  24. 600
  25. 3200
  26. 1100
  27. 1200
  28. 1000
  29. 1000
  30. 8100
  31. 900
  32. 1400
  33. 1300
  34. 1500
  35. 800
  36. 3500
  37. 900
  38. 1400
  39. 1200
  40. 800

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