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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 473 · 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 22 × 58? (a) 1200 (b) 12000 (c) 120
  2. 2.Best estimate of 158 + 310? (a) 300 (b) 700 (c) 500
  3. 3.Best estimate of 845 + 387? (a) 1400 (b) 1000 (c) 1200
  4. 4.Best estimate of 20 × 46? (a) 1000 (b) 10000 (c) 100
  5. 5.Best estimate of 174 + 440? (a) 600 (b) 800 (c) 400
  6. 6.Best estimate of 19 × 17? (a) 400 (b) 40 (c) 4000
  7. 7.Best estimate of 635 + 456? (a) 1300 (b) 1100 (c) 900
  8. 8.Best estimate of 710 + 314? (a) 1000 (b) 1200 (c) 800
  9. 9.Best estimate of 789 + 497? (a) 1300 (b) 1500 (c) 1100
  10. 10.Best estimate of 794 + 789? (a) 1400 (b) 1800 (c) 1600
  11. 11.Best estimate of 22 × 86? (a) 1800 (b) 18000 (c) 180
  12. 12.Best estimate of 49 × 36? (a) 20000 (b) 2000 (c) 200
  13. 13.Best estimate of 410 + 272? (a) 500 (b) 700 (c) 900
  14. 14.Best estimate of 61 × 82? (a) 4800 (b) 480 (c) 48000
  15. 15.Best estimate of 54 × 14? (a) 500 (b) 5000 (c) 50
  16. 16.Best estimate of 414 + 235? (a) 800 (b) 400 (c) 600
  17. 17.Best estimate of 689 + 505? (a) 1000 (b) 1400 (c) 1200
  18. 18.Best estimate of 276 + 236? (a) 300 (b) 700 (c) 500
  19. 19.Best estimate of 66 × 90? (a) 630 (b) 6300 (c) 63000
  20. 20.Best estimate of 17 × 56? (a) 12000 (b) 120 (c) 1200
  21. 21.Best estimate of 143 + 662? (a) 1000 (b) 800 (c) 600
  22. 22.Best estimate of 487 + 514? (a) 800 (b) 1000 (c) 1200
  23. 23.Best estimate of 40 × 86? (a) 36000 (b) 360 (c) 3600
  24. 24.Best estimate of 163 + 167? (a) 200 (b) 600 (c) 400
  25. 25.Best estimate of 772 + 272? (a) 1100 (b) 1300 (c) 900
  26. 26.Best estimate of 299 + 178? (a) 300 (b) 500 (c) 700
  27. 27.Best estimate of 518 + 598? (a) 900 (b) 1100 (c) 1300
  28. 28.Best estimate of 66 × 96? (a) 70000 (b) 700 (c) 7000
  29. 29.Best estimate of 528 + 478? (a) 800 (b) 1000 (c) 1200
  30. 30.Best estimate of 96 × 98? (a) 1000 (b) 10000 (c) 100000
  31. 31.Best estimate of 97 × 16? (a) 200 (b) 20000 (c) 2000
  32. 32.Best estimate of 76 × 70? (a) 560 (b) 5600 (c) 56000
  33. 33.Best estimate of 495 + 184? (a) 900 (b) 500 (c) 700
  34. 34.Best estimate of 644 + 507? (a) 900 (b) 1300 (c) 1100
  35. 35.Best estimate of 66 × 76? (a) 560 (b) 5600 (c) 56000
  36. 36.Best estimate of 43 × 66? (a) 280 (b) 28000 (c) 2800
  37. 37.Best estimate of 177 + 331? (a) 500 (b) 700 (c) 300
  38. 38.Best estimate of 57 × 88? (a) 54000 (b) 5400 (c) 540
  39. 39.Best estimate of 26 × 80? (a) 2400 (b) 240 (c) 24000
  40. 40.Best estimate of 31 × 94? (a) 270 (b) 27000 (c) 2700

Answer key

  1. 1200
  2. 500
  3. 1200
  4. 1000
  5. 600
  6. 400
  7. 1100
  8. 1000
  9. 1300
  10. 1600
  11. 1800
  12. 2000
  13. 700
  14. 4800
  15. 500
  16. 600
  17. 1200
  18. 500
  19. 6300
  20. 1200
  21. 800
  22. 1000
  23. 3600
  24. 400
  25. 1100
  26. 500
  27. 1100
  28. 7000
  29. 1000
  30. 10000
  31. 2000
  32. 5600
  33. 700
  34. 1100
  35. 5600
  36. 2800
  37. 500
  38. 5400
  39. 2400
  40. 2700

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