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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 440 · 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 691 + 188? (a) 700 (b) 900 (c) 1100
  2. 2.Best estimate of 502 + 514? (a) 800 (b) 1000 (c) 1200
  3. 3.Best estimate of 859 + 258? (a) 1400 (b) 1000 (c) 1200
  4. 4.Best estimate of 757 + 170? (a) 800 (b) 1000 (c) 1200
  5. 5.Best estimate of 56 × 91? (a) 5400 (b) 54000 (c) 540
  6. 6.Best estimate of 520 + 257? (a) 800 (b) 1000 (c) 600
  7. 7.Best estimate of 88 × 73? (a) 6300 (b) 630 (c) 63000
  8. 8.Best estimate of 52 × 33? (a) 15000 (b) 1500 (c) 150
  9. 9.Best estimate of 94 × 84? (a) 7200 (b) 720 (c) 72000
  10. 10.Best estimate of 174 + 566? (a) 800 (b) 600 (c) 1000
  11. 11.Best estimate of 264 + 468? (a) 800 (b) 1000 (c) 600
  12. 12.Best estimate of 27 × 19? (a) 600 (b) 60 (c) 6000
  13. 13.Best estimate of 79 × 86? (a) 720 (b) 7200 (c) 72000
  14. 14.Best estimate of 559 + 724? (a) 1500 (b) 1100 (c) 1300
  15. 15.Best estimate of 27 × 73? (a) 2100 (b) 21000 (c) 210
  16. 16.Best estimate of 64 × 24? (a) 12000 (b) 120 (c) 1200
  17. 17.Best estimate of 66 × 47? (a) 35000 (b) 350 (c) 3500
  18. 18.Best estimate of 37 × 86? (a) 360 (b) 3600 (c) 36000
  19. 19.Best estimate of 32 × 56? (a) 18000 (b) 180 (c) 1800
  20. 20.Best estimate of 473 + 360? (a) 900 (b) 700 (c) 1100
  21. 21.Best estimate of 430 + 225? (a) 600 (b) 800 (c) 400
  22. 22.Best estimate of 76 × 32? (a) 24000 (b) 2400 (c) 240
  23. 23.Best estimate of 580 + 620? (a) 1200 (b) 1400 (c) 1000
  24. 24.Best estimate of 98 × 86? (a) 900 (b) 90000 (c) 9000
  25. 25.Best estimate of 851 + 825? (a) 1900 (b) 1700 (c) 1500
  26. 26.Best estimate of 528 + 421? (a) 1100 (b) 900 (c) 700
  27. 27.Best estimate of 535 + 265? (a) 800 (b) 600 (c) 1000
  28. 28.Best estimate of 23 × 36? (a) 800 (b) 80 (c) 8000
  29. 29.Best estimate of 709 + 796? (a) 1500 (b) 1300 (c) 1700
  30. 30.Best estimate of 838 + 559? (a) 1600 (b) 1200 (c) 1400
  31. 31.Best estimate of 34 × 81? (a) 240 (b) 2400 (c) 24000
  32. 32.Best estimate of 76 × 62? (a) 48000 (b) 4800 (c) 480
  33. 33.Best estimate of 40 × 67? (a) 280 (b) 28000 (c) 2800
  34. 34.Best estimate of 384 + 800? (a) 1000 (b) 1400 (c) 1200
  35. 35.Best estimate of 76 × 79? (a) 64000 (b) 6400 (c) 640
  36. 36.Best estimate of 157 + 159? (a) 200 (b) 600 (c) 400
  37. 37.Best estimate of 474 + 477? (a) 1000 (b) 1200 (c) 800
  38. 38.Best estimate of 61 × 76? (a) 4800 (b) 48000 (c) 480
  39. 39.Best estimate of 217 + 651? (a) 900 (b) 700 (c) 1100
  40. 40.Best estimate of 26 × 19? (a) 60 (b) 6000 (c) 600

Answer key

  1. 900
  2. 1000
  3. 1200
  4. 1000
  5. 5400
  6. 800
  7. 6300
  8. 1500
  9. 7200
  10. 800
  11. 800
  12. 600
  13. 7200
  14. 1300
  15. 2100
  16. 1200
  17. 3500
  18. 3600
  19. 1800
  20. 900
  21. 600
  22. 2400
  23. 1200
  24. 9000
  25. 1700
  26. 900
  27. 800
  28. 800
  29. 1500
  30. 1400
  31. 2400
  32. 4800
  33. 2800
  34. 1200
  35. 6400
  36. 400
  37. 1000
  38. 4800
  39. 900
  40. 600

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