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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 577 · 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 43 × 87? (a) 36000 (b) 360 (c) 3600
  2. 2.Best estimate of 802 + 541? (a) 1300 (b) 1100 (c) 1500
  3. 3.Best estimate of 311 + 529? (a) 800 (b) 600 (c) 1000
  4. 4.Best estimate of 70 × 21? (a) 1400 (b) 14000 (c) 140
  5. 5.Best estimate of 533 + 229? (a) 900 (b) 500 (c) 700
  6. 6.Best estimate of 236 + 143? (a) 300 (b) 500 (c) 100
  7. 7.Best estimate of 198 + 179? (a) 400 (b) 200 (c) 600
  8. 8.Best estimate of 50 × 60? (a) 300 (b) 30000 (c) 3000
  9. 9.Best estimate of 136 + 775? (a) 700 (b) 900 (c) 1100
  10. 10.Best estimate of 96 × 26? (a) 300 (b) 30000 (c) 3000
  11. 11.Best estimate of 417 + 314? (a) 700 (b) 900 (c) 500
  12. 12.Best estimate of 79 × 93? (a) 7200 (b) 720 (c) 72000
  13. 13.Best estimate of 748 + 505? (a) 1200 (b) 1000 (c) 1400
  14. 14.Best estimate of 64 × 21? (a) 1200 (b) 12000 (c) 120
  15. 15.Best estimate of 24 × 96? (a) 2000 (b) 200 (c) 20000
  16. 16.Best estimate of 43 × 84? (a) 320 (b) 32000 (c) 3200
  17. 17.Best estimate of 69 × 28? (a) 21000 (b) 210 (c) 2100
  18. 18.Best estimate of 96 × 17? (a) 2000 (b) 200 (c) 20000
  19. 19.Best estimate of 391 + 464? (a) 700 (b) 900 (c) 1100
  20. 20.Best estimate of 314 + 705? (a) 1000 (b) 1200 (c) 800
  21. 21.Best estimate of 227 + 475? (a) 900 (b) 700 (c) 500
  22. 22.Best estimate of 216 + 651? (a) 900 (b) 1100 (c) 700
  23. 23.Best estimate of 36 × 28? (a) 120 (b) 1200 (c) 12000
  24. 24.Best estimate of 306 + 352? (a) 900 (b) 500 (c) 700
  25. 25.Best estimate of 247 + 753? (a) 1000 (b) 1200 (c) 800
  26. 26.Best estimate of 558 + 311? (a) 1100 (b) 900 (c) 700
  27. 27.Best estimate of 310 + 588? (a) 900 (b) 1100 (c) 700
  28. 28.Best estimate of 18 × 93? (a) 1800 (b) 18000 (c) 180
  29. 29.Best estimate of 66 × 67? (a) 4900 (b) 49000 (c) 490
  30. 30.Best estimate of 60 × 66? (a) 420 (b) 42000 (c) 4200
  31. 31.Best estimate of 44 × 14? (a) 400 (b) 40 (c) 4000
  32. 32.Best estimate of 92 × 26? (a) 270 (b) 27000 (c) 2700
  33. 33.Best estimate of 555 + 504? (a) 1100 (b) 900 (c) 1300
  34. 34.Best estimate of 52 × 73? (a) 35000 (b) 350 (c) 3500
  35. 35.Best estimate of 91 × 73? (a) 630 (b) 6300 (c) 63000
  36. 36.Best estimate of 290 + 551? (a) 1100 (b) 900 (c) 700
  37. 37.Best estimate of 414 + 134? (a) 300 (b) 500 (c) 700
  38. 38.Best estimate of 705 + 564? (a) 1500 (b) 1100 (c) 1300
  39. 39.Best estimate of 67 × 97? (a) 70000 (b) 700 (c) 7000
  40. 40.Best estimate of 39 × 16? (a) 80 (b) 8000 (c) 800

Answer key

  1. 3600
  2. 1300
  3. 800
  4. 1400
  5. 700
  6. 300
  7. 400
  8. 3000
  9. 900
  10. 3000
  11. 700
  12. 7200
  13. 1200
  14. 1200
  15. 2000
  16. 3200
  17. 2100
  18. 2000
  19. 900
  20. 1000
  21. 700
  22. 900
  23. 1200
  24. 700
  25. 1000
  26. 900
  27. 900
  28. 1800
  29. 4900
  30. 4200
  31. 400
  32. 2700
  33. 1100
  34. 3500
  35. 6300
  36. 900
  37. 500
  38. 1300
  39. 7000
  40. 800

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