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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 281 · 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 264 + 456? (a) 1000 (b) 800 (c) 600
  2. 2.Best estimate of 26 × 23? (a) 6000 (b) 600 (c) 60
  3. 3.Best estimate of 143 + 574? (a) 900 (b) 500 (c) 700
  4. 4.Best estimate of 326 + 796? (a) 900 (b) 1300 (c) 1100
  5. 5.Best estimate of 30 × 53? (a) 150 (b) 15000 (c) 1500
  6. 6.Best estimate of 71 × 43? (a) 28000 (b) 280 (c) 2800
  7. 7.Best estimate of 193 + 242? (a) 400 (b) 600 (c) 200
  8. 8.Best estimate of 452 + 328? (a) 600 (b) 1000 (c) 800
  9. 9.Best estimate of 431 + 132? (a) 700 (b) 300 (c) 500
  10. 10.Best estimate of 678 + 193? (a) 1100 (b) 900 (c) 700
  11. 11.Best estimate of 66 × 56? (a) 42000 (b) 4200 (c) 420
  12. 12.Best estimate of 826 + 673? (a) 1500 (b) 1700 (c) 1300
  13. 13.Best estimate of 93 × 56? (a) 540 (b) 54000 (c) 5400
  14. 14.Best estimate of 766 + 400? (a) 1000 (b) 1400 (c) 1200
  15. 15.Best estimate of 382 + 645? (a) 1000 (b) 1200 (c) 800
  16. 16.Best estimate of 19 × 12? (a) 20 (b) 2000 (c) 200
  17. 17.Best estimate of 842 + 615? (a) 1600 (b) 1200 (c) 1400
  18. 18.Best estimate of 147 + 842? (a) 900 (b) 700 (c) 1100
  19. 19.Best estimate of 285 + 457? (a) 600 (b) 1000 (c) 800
  20. 20.Best estimate of 76 × 20? (a) 160 (b) 1600 (c) 16000
  21. 21.Best estimate of 246 + 484? (a) 500 (b) 700 (c) 900
  22. 22.Best estimate of 664 + 349? (a) 800 (b) 1200 (c) 1000
  23. 23.Best estimate of 49 × 92? (a) 45000 (b) 450 (c) 4500
  24. 24.Best estimate of 78 × 66? (a) 5600 (b) 56000 (c) 560
  25. 25.Best estimate of 16 × 97? (a) 2000 (b) 200 (c) 20000
  26. 26.Best estimate of 606 + 123? (a) 700 (b) 500 (c) 900
  27. 27.Best estimate of 362 + 476? (a) 1100 (b) 700 (c) 900
  28. 28.Best estimate of 624 + 500? (a) 1300 (b) 1100 (c) 900
  29. 29.Best estimate of 388 + 243? (a) 800 (b) 400 (c) 600
  30. 30.Best estimate of 316 + 151? (a) 500 (b) 700 (c) 300
  31. 31.Best estimate of 236 + 728? (a) 700 (b) 1100 (c) 900
  32. 32.Best estimate of 88 × 16? (a) 18000 (b) 1800 (c) 180
  33. 33.Best estimate of 16 × 67? (a) 1400 (b) 14000 (c) 140
  34. 34.Best estimate of 97 × 50? (a) 50000 (b) 5000 (c) 500
  35. 35.Best estimate of 770 + 152? (a) 1200 (b) 1000 (c) 800
  36. 36.Best estimate of 123 + 294? (a) 400 (b) 600 (c) 200
  37. 37.Best estimate of 96 × 89? (a) 90000 (b) 9000 (c) 900
  38. 38.Best estimate of 294 + 467? (a) 800 (b) 1000 (c) 600
  39. 39.Best estimate of 28 × 36? (a) 120 (b) 1200 (c) 12000
  40. 40.Best estimate of 199 + 696? (a) 700 (b) 900 (c) 1100

Answer key

  1. 800
  2. 600
  3. 700
  4. 1100
  5. 1500
  6. 2800
  7. 400
  8. 800
  9. 500
  10. 900
  11. 4200
  12. 1500
  13. 5400
  14. 1200
  15. 1000
  16. 200
  17. 1400
  18. 900
  19. 800
  20. 1600
  21. 700
  22. 1000
  23. 4500
  24. 5600
  25. 2000
  26. 700
  27. 900
  28. 1100
  29. 600
  30. 500
  31. 900
  32. 1800
  33. 1400
  34. 5000
  35. 1000
  36. 400
  37. 9000
  38. 800
  39. 1200
  40. 900

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