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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 15 · 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 667 + 565? (a) 1100 (b) 1300 (c) 1500
  2. 2.Best estimate of 72 × 98? (a) 700 (b) 7000 (c) 70000
  3. 3.Best estimate of 228 + 611? (a) 1000 (b) 800 (c) 600
  4. 4.Best estimate of 86 × 47? (a) 450 (b) 45000 (c) 4500
  5. 5.Best estimate of 429 + 812? (a) 1200 (b) 1000 (c) 1400
  6. 6.Best estimate of 36 × 87? (a) 36000 (b) 360 (c) 3600
  7. 7.Best estimate of 255 + 333? (a) 800 (b) 400 (c) 600
  8. 8.Best estimate of 228 + 175? (a) 400 (b) 200 (c) 600
  9. 9.Best estimate of 59 × 54? (a) 30000 (b) 300 (c) 3000
  10. 10.Best estimate of 187 + 454? (a) 700 (b) 500 (c) 900
  11. 11.Best estimate of 89 × 96? (a) 900 (b) 9000 (c) 90000
  12. 12.Best estimate of 12 × 56? (a) 6000 (b) 60 (c) 600
  13. 13.Best estimate of 74 × 31? (a) 210 (b) 2100 (c) 21000
  14. 14.Best estimate of 837 + 407? (a) 1200 (b) 1000 (c) 1400
  15. 15.Best estimate of 56 × 17? (a) 1200 (b) 12000 (c) 120
  16. 16.Best estimate of 22 × 34? (a) 600 (b) 6000 (c) 60
  17. 17.Best estimate of 674 + 808? (a) 1500 (b) 1700 (c) 1300
  18. 18.Best estimate of 478 + 290? (a) 800 (b) 600 (c) 1000
  19. 19.Best estimate of 13 × 56? (a) 600 (b) 6000 (c) 60
  20. 20.Best estimate of 584 + 214? (a) 1000 (b) 600 (c) 800
  21. 21.Best estimate of 50 × 18? (a) 100 (b) 1000 (c) 10000
  22. 22.Best estimate of 38 × 17? (a) 8000 (b) 80 (c) 800
  23. 23.Best estimate of 197 + 283? (a) 500 (b) 300 (c) 700
  24. 24.Best estimate of 348 + 486? (a) 1000 (b) 600 (c) 800
  25. 25.Best estimate of 61 × 36? (a) 2400 (b) 24000 (c) 240
  26. 26.Best estimate of 83 × 29? (a) 24000 (b) 240 (c) 2400
  27. 27.Best estimate of 53 × 67? (a) 350 (b) 35000 (c) 3500
  28. 28.Best estimate of 873 + 647? (a) 1500 (b) 1300 (c) 1700
  29. 29.Best estimate of 32 × 27? (a) 90 (b) 900 (c) 9000
  30. 30.Best estimate of 187 + 213? (a) 600 (b) 200 (c) 400
  31. 31.Best estimate of 74 × 53? (a) 350 (b) 3500 (c) 35000
  32. 32.Best estimate of 453 + 436? (a) 900 (b) 1100 (c) 700
  33. 33.Best estimate of 384 + 543? (a) 1100 (b) 700 (c) 900
  34. 34.Best estimate of 78 × 66? (a) 560 (b) 56000 (c) 5600
  35. 35.Best estimate of 91 × 98? (a) 9000 (b) 900 (c) 90000
  36. 36.Best estimate of 52 × 47? (a) 250 (b) 25000 (c) 2500
  37. 37.Best estimate of 507 + 136? (a) 400 (b) 800 (c) 600
  38. 38.Best estimate of 17 × 16? (a) 40 (b) 400 (c) 4000
  39. 39.Best estimate of 859 + 384? (a) 1500 (b) 1100 (c) 1300
  40. 40.Best estimate of 20 × 34? (a) 60 (b) 6000 (c) 600

Answer key

  1. 1300
  2. 7000
  3. 800
  4. 4500
  5. 1200
  6. 3600
  7. 600
  8. 400
  9. 3000
  10. 700
  11. 9000
  12. 600
  13. 2100
  14. 1200
  15. 1200
  16. 600
  17. 1500
  18. 800
  19. 600
  20. 800
  21. 1000
  22. 800
  23. 500
  24. 800
  25. 2400
  26. 2400
  27. 3500
  28. 1500
  29. 900
  30. 400
  31. 3500
  32. 900
  33. 900
  34. 5600
  35. 9000
  36. 2500
  37. 600
  38. 400
  39. 1300
  40. 600

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