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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 234 · 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 836 + 404? (a) 1200 (b) 1000 (c) 1400
  2. 2.Best estimate of 36 × 40? (a) 1600 (b) 16000 (c) 160
  3. 3.Best estimate of 178 + 192? (a) 400 (b) 600 (c) 200
  4. 4.Best estimate of 867 + 630? (a) 1700 (b) 1500 (c) 1300
  5. 5.Best estimate of 275 + 336? (a) 600 (b) 400 (c) 800
  6. 6.Best estimate of 585 + 742? (a) 1100 (b) 1500 (c) 1300
  7. 7.Best estimate of 86 × 80? (a) 7200 (b) 72000 (c) 720
  8. 8.Best estimate of 604 + 441? (a) 1000 (b) 800 (c) 1200
  9. 9.Best estimate of 290 + 238? (a) 500 (b) 300 (c) 700
  10. 10.Best estimate of 304 + 152? (a) 500 (b) 700 (c) 300
  11. 11.Best estimate of 81 × 14? (a) 8000 (b) 800 (c) 80
  12. 12.Best estimate of 838 + 137? (a) 1100 (b) 900 (c) 700
  13. 13.Best estimate of 852 + 207? (a) 1300 (b) 1100 (c) 900
  14. 14.Best estimate of 16 × 66? (a) 140 (b) 1400 (c) 14000
  15. 15.Best estimate of 375 + 446? (a) 800 (b) 600 (c) 1000
  16. 16.Best estimate of 71 × 54? (a) 350 (b) 35000 (c) 3500
  17. 17.Best estimate of 58 × 16? (a) 12000 (b) 1200 (c) 120
  18. 18.Best estimate of 500 + 572? (a) 1100 (b) 1300 (c) 900
  19. 19.Best estimate of 26 × 53? (a) 1500 (b) 150 (c) 15000
  20. 20.Best estimate of 93 × 41? (a) 36000 (b) 3600 (c) 360
  21. 21.Best estimate of 877 + 335? (a) 1200 (b) 1000 (c) 1400
  22. 22.Best estimate of 228 + 838? (a) 1000 (b) 800 (c) 1200
  23. 23.Best estimate of 59 × 54? (a) 300 (b) 3000 (c) 30000
  24. 24.Best estimate of 61 × 21? (a) 120 (b) 12000 (c) 1200
  25. 25.Best estimate of 26 × 16? (a) 6000 (b) 600 (c) 60
  26. 26.Best estimate of 823 + 188? (a) 1200 (b) 1000 (c) 800
  27. 27.Best estimate of 297 + 375? (a) 500 (b) 700 (c) 900
  28. 28.Best estimate of 13 × 21? (a) 200 (b) 2000 (c) 20
  29. 29.Best estimate of 373 + 676? (a) 900 (b) 1100 (c) 1300
  30. 30.Best estimate of 84 × 56? (a) 48000 (b) 4800 (c) 480
  31. 31.Best estimate of 766 + 225? (a) 1000 (b) 1200 (c) 800
  32. 32.Best estimate of 740 + 288? (a) 1000 (b) 800 (c) 1200
  33. 33.Best estimate of 613 + 191? (a) 800 (b) 1000 (c) 600
  34. 34.Best estimate of 822 + 566? (a) 1600 (b) 1200 (c) 1400
  35. 35.Best estimate of 21 × 81? (a) 1600 (b) 160 (c) 16000
  36. 36.Best estimate of 178 + 480? (a) 700 (b) 500 (c) 900
  37. 37.Best estimate of 30 × 32? (a) 90 (b) 900 (c) 9000
  38. 38.Best estimate of 16 × 30? (a) 60 (b) 6000 (c) 600
  39. 39.Best estimate of 849 + 752? (a) 1400 (b) 1800 (c) 1600
  40. 40.Best estimate of 302 + 311? (a) 400 (b) 800 (c) 600

Answer key

  1. 1200
  2. 1600
  3. 400
  4. 1500
  5. 600
  6. 1300
  7. 7200
  8. 1000
  9. 500
  10. 500
  11. 800
  12. 900
  13. 1100
  14. 1400
  15. 800
  16. 3500
  17. 1200
  18. 1100
  19. 1500
  20. 3600
  21. 1200
  22. 1000
  23. 3000
  24. 1200
  25. 600
  26. 1000
  27. 700
  28. 200
  29. 1100
  30. 4800
  31. 1000
  32. 1000
  33. 800
  34. 1400
  35. 1600
  36. 700
  37. 900
  38. 600
  39. 1600
  40. 600

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