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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 886 · 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 256 + 451? (a) 1000 (b) 600 (c) 800
  2. 2.Best estimate of 760 + 398? (a) 1200 (b) 1400 (c) 1000
  3. 3.Best estimate of 569 + 853? (a) 1300 (b) 1700 (c) 1500
  4. 4.Best estimate of 56 × 68? (a) 4200 (b) 420 (c) 42000
  5. 5.Best estimate of 639 + 153? (a) 1000 (b) 800 (c) 600
  6. 6.Best estimate of 16 × 26? (a) 600 (b) 6000 (c) 60
  7. 7.Best estimate of 59 × 70? (a) 420 (b) 4200 (c) 42000
  8. 8.Best estimate of 78 × 73? (a) 56000 (b) 5600 (c) 560
  9. 9.Best estimate of 70 × 22? (a) 140 (b) 14000 (c) 1400
  10. 10.Best estimate of 47 × 19? (a) 100 (b) 10000 (c) 1000
  11. 11.Best estimate of 90 × 96? (a) 9000 (b) 90000 (c) 900
  12. 12.Best estimate of 426 + 518? (a) 700 (b) 900 (c) 1100
  13. 13.Best estimate of 86 × 50? (a) 45000 (b) 4500 (c) 450
  14. 14.Best estimate of 53 × 61? (a) 3000 (b) 300 (c) 30000
  15. 15.Best estimate of 68 × 41? (a) 280 (b) 2800 (c) 28000
  16. 16.Best estimate of 17 × 16? (a) 4000 (b) 40 (c) 400
  17. 17.Best estimate of 61 × 40? (a) 240 (b) 24000 (c) 2400
  18. 18.Best estimate of 26 × 17? (a) 600 (b) 60 (c) 6000
  19. 19.Best estimate of 190 + 507? (a) 700 (b) 900 (c) 500
  20. 20.Best estimate of 73 × 16? (a) 14000 (b) 140 (c) 1400
  21. 21.Best estimate of 283 + 328? (a) 800 (b) 400 (c) 600
  22. 22.Best estimate of 56 × 48? (a) 3000 (b) 30000 (c) 300
  23. 23.Best estimate of 30 × 94? (a) 2700 (b) 270 (c) 27000
  24. 24.Best estimate of 94 × 92? (a) 8100 (b) 81000 (c) 810
  25. 25.Best estimate of 767 + 156? (a) 1200 (b) 800 (c) 1000
  26. 26.Best estimate of 792 + 164? (a) 1200 (b) 800 (c) 1000
  27. 27.Best estimate of 146 + 398? (a) 700 (b) 500 (c) 300
  28. 28.Best estimate of 239 + 821? (a) 1000 (b) 1200 (c) 800
  29. 29.Best estimate of 46 × 76? (a) 400 (b) 4000 (c) 40000
  30. 30.Best estimate of 463 + 854? (a) 1200 (b) 1400 (c) 1600
  31. 31.Best estimate of 44 × 80? (a) 320 (b) 32000 (c) 3200
  32. 32.Best estimate of 68 × 62? (a) 42000 (b) 420 (c) 4200
  33. 33.Best estimate of 83 × 68? (a) 560 (b) 5600 (c) 56000
  34. 34.Best estimate of 809 + 440? (a) 1200 (b) 1000 (c) 1400
  35. 35.Best estimate of 733 + 155? (a) 1100 (b) 900 (c) 700
  36. 36.Best estimate of 770 + 491? (a) 1300 (b) 1100 (c) 1500
  37. 37.Best estimate of 307 + 294? (a) 600 (b) 800 (c) 400
  38. 38.Best estimate of 272 + 651? (a) 1200 (b) 1000 (c) 800
  39. 39.Best estimate of 13 × 80? (a) 8000 (b) 800 (c) 80
  40. 40.Best estimate of 216 + 664? (a) 900 (b) 700 (c) 1100

Answer key

  1. 800
  2. 1200
  3. 1500
  4. 4200
  5. 800
  6. 600
  7. 4200
  8. 5600
  9. 1400
  10. 1000
  11. 9000
  12. 900
  13. 4500
  14. 3000
  15. 2800
  16. 400
  17. 2400
  18. 600
  19. 700
  20. 1400
  21. 600
  22. 3000
  23. 2700
  24. 8100
  25. 1000
  26. 1000
  27. 500
  28. 1000
  29. 4000
  30. 1400
  31. 3200
  32. 4200
  33. 5600
  34. 1200
  35. 900
  36. 1300
  37. 600
  38. 1000
  39. 800
  40. 900

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