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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 504 · 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 70 × 78? (a) 5600 (b) 56000 (c) 560
  2. 2.Best estimate of 808 + 223? (a) 800 (b) 1200 (c) 1000
  3. 3.Best estimate of 655 + 392? (a) 900 (b) 1100 (c) 1300
  4. 4.Best estimate of 59 × 98? (a) 6000 (b) 60000 (c) 600
  5. 5.Best estimate of 344 + 515? (a) 600 (b) 1000 (c) 800
  6. 6.Best estimate of 120 + 484? (a) 800 (b) 600 (c) 400
  7. 7.Best estimate of 153 + 797? (a) 1000 (b) 1200 (c) 800
  8. 8.Best estimate of 41 × 66? (a) 280 (b) 2800 (c) 28000
  9. 9.Best estimate of 548 + 861? (a) 1200 (b) 1600 (c) 1400
  10. 10.Best estimate of 651 + 629? (a) 1300 (b) 1500 (c) 1100
  11. 11.Best estimate of 40 × 90? (a) 360 (b) 36000 (c) 3600
  12. 12.Best estimate of 486 + 533? (a) 1000 (b) 800 (c) 1200
  13. 13.Best estimate of 47 × 73? (a) 35000 (b) 3500 (c) 350
  14. 14.Best estimate of 429 + 338? (a) 900 (b) 700 (c) 500
  15. 15.Best estimate of 36 × 19? (a) 80 (b) 8000 (c) 800
  16. 16.Best estimate of 634 + 764? (a) 1400 (b) 1600 (c) 1200
  17. 17.Best estimate of 38 × 86? (a) 360 (b) 36000 (c) 3600
  18. 18.Best estimate of 76 × 28? (a) 24000 (b) 2400 (c) 240
  19. 19.Best estimate of 38 × 59? (a) 240 (b) 24000 (c) 2400
  20. 20.Best estimate of 36 × 29? (a) 12000 (b) 120 (c) 1200
  21. 21.Best estimate of 26 × 61? (a) 18000 (b) 1800 (c) 180
  22. 22.Best estimate of 71 × 52? (a) 35000 (b) 350 (c) 3500
  23. 23.Best estimate of 12 × 30? (a) 3000 (b) 300 (c) 30
  24. 24.Best estimate of 61 × 83? (a) 48000 (b) 4800 (c) 480
  25. 25.Best estimate of 14 × 56? (a) 6000 (b) 600 (c) 60
  26. 26.Best estimate of 43 × 13? (a) 400 (b) 4000 (c) 40
  27. 27.Best estimate of 623 + 251? (a) 700 (b) 1100 (c) 900
  28. 28.Best estimate of 58 × 13? (a) 60 (b) 600 (c) 6000
  29. 29.Best estimate of 709 + 254? (a) 1200 (b) 800 (c) 1000
  30. 30.Best estimate of 26 × 63? (a) 18000 (b) 180 (c) 1800
  31. 31.Best estimate of 534 + 741? (a) 1200 (b) 1400 (c) 1000
  32. 32.Best estimate of 79 × 50? (a) 40000 (b) 400 (c) 4000
  33. 33.Best estimate of 699 + 722? (a) 1200 (b) 1600 (c) 1400
  34. 34.Best estimate of 860 + 152? (a) 1300 (b) 900 (c) 1100
  35. 35.Best estimate of 58 × 31? (a) 1800 (b) 18000 (c) 180
  36. 36.Best estimate of 276 + 584? (a) 900 (b) 700 (c) 1100
  37. 37.Best estimate of 53 × 40? (a) 2000 (b) 200 (c) 20000
  38. 38.Best estimate of 860 + 489? (a) 1600 (b) 1400 (c) 1200
  39. 39.Best estimate of 82 × 66? (a) 5600 (b) 560 (c) 56000
  40. 40.Best estimate of 47 × 14? (a) 5000 (b) 50 (c) 500

Answer key

  1. 5600
  2. 1000
  3. 1100
  4. 6000
  5. 800
  6. 600
  7. 1000
  8. 2800
  9. 1400
  10. 1300
  11. 3600
  12. 1000
  13. 3500
  14. 700
  15. 800
  16. 1400
  17. 3600
  18. 2400
  19. 2400
  20. 1200
  21. 1800
  22. 3500
  23. 300
  24. 4800
  25. 600
  26. 400
  27. 900
  28. 600
  29. 1000
  30. 1800
  31. 1200
  32. 4000
  33. 1400
  34. 1100
  35. 1800
  36. 900
  37. 2000
  38. 1400
  39. 5600
  40. 500

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