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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 888 · 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 586 + 813? (a) 1400 (b) 1600 (c) 1200
  2. 2.Best estimate of 558 + 222? (a) 600 (b) 1000 (c) 800
  3. 3.Best estimate of 331 + 399? (a) 700 (b) 500 (c) 900
  4. 4.Best estimate of 845 + 143? (a) 700 (b) 1100 (c) 900
  5. 5.Best estimate of 232 + 536? (a) 500 (b) 900 (c) 700
  6. 6.Best estimate of 23 × 41? (a) 800 (b) 80 (c) 8000
  7. 7.Best estimate of 206 + 717? (a) 900 (b) 1100 (c) 700
  8. 8.Best estimate of 718 + 564? (a) 1500 (b) 1300 (c) 1100
  9. 9.Best estimate of 88 × 76? (a) 7200 (b) 720 (c) 72000
  10. 10.Best estimate of 314 + 311? (a) 400 (b) 600 (c) 800
  11. 11.Best estimate of 457 + 178? (a) 700 (b) 900 (c) 500
  12. 12.Best estimate of 447 + 271? (a) 900 (b) 700 (c) 500
  13. 13.Best estimate of 764 + 772? (a) 1600 (b) 1800 (c) 1400
  14. 14.Best estimate of 91 × 32? (a) 27000 (b) 2700 (c) 270
  15. 15.Best estimate of 222 + 681? (a) 900 (b) 1100 (c) 700
  16. 16.Best estimate of 13 × 37? (a) 4000 (b) 40 (c) 400
  17. 17.Best estimate of 93 × 56? (a) 5400 (b) 54000 (c) 540
  18. 18.Best estimate of 86 × 80? (a) 72000 (b) 720 (c) 7200
  19. 19.Best estimate of 700 + 151? (a) 700 (b) 1100 (c) 900
  20. 20.Best estimate of 89 × 64? (a) 5400 (b) 540 (c) 54000
  21. 21.Best estimate of 16 × 22? (a) 40 (b) 400 (c) 4000
  22. 22.Best estimate of 12 × 59? (a) 60 (b) 600 (c) 6000
  23. 23.Best estimate of 195 + 840? (a) 1200 (b) 800 (c) 1000
  24. 24.Best estimate of 39 × 73? (a) 2800 (b) 280 (c) 28000
  25. 25.Best estimate of 814 + 395? (a) 1400 (b) 1200 (c) 1000
  26. 26.Best estimate of 30 × 74? (a) 2100 (b) 21000 (c) 210
  27. 27.Best estimate of 814 + 283? (a) 1100 (b) 900 (c) 1300
  28. 28.Best estimate of 584 + 635? (a) 1400 (b) 1000 (c) 1200
  29. 29.Best estimate of 177 + 365? (a) 400 (b) 800 (c) 600
  30. 30.Best estimate of 522 + 572? (a) 1100 (b) 900 (c) 1300
  31. 31.Best estimate of 137 + 704? (a) 600 (b) 1000 (c) 800
  32. 32.Best estimate of 634 + 687? (a) 1100 (b) 1300 (c) 1500
  33. 33.Best estimate of 66 × 62? (a) 420 (b) 42000 (c) 4200
  34. 34.Best estimate of 83 × 33? (a) 2400 (b) 240 (c) 24000
  35. 35.Best estimate of 37 × 83? (a) 320 (b) 32000 (c) 3200
  36. 36.Best estimate of 22 × 36? (a) 800 (b) 8000 (c) 80
  37. 37.Best estimate of 74 × 17? (a) 1400 (b) 140 (c) 14000
  38. 38.Best estimate of 714 + 594? (a) 1500 (b) 1300 (c) 1100
  39. 39.Best estimate of 31 × 33? (a) 90 (b) 9000 (c) 900
  40. 40.Best estimate of 33 × 46? (a) 1500 (b) 15000 (c) 150

Answer key

  1. 1400
  2. 800
  3. 700
  4. 900
  5. 700
  6. 800
  7. 900
  8. 1300
  9. 7200
  10. 600
  11. 700
  12. 700
  13. 1600
  14. 2700
  15. 900
  16. 400
  17. 5400
  18. 7200
  19. 900
  20. 5400
  21. 400
  22. 600
  23. 1000
  24. 2800
  25. 1200
  26. 2100
  27. 1100
  28. 1200
  29. 600
  30. 1100
  31. 800
  32. 1300
  33. 4200
  34. 2400
  35. 3200
  36. 800
  37. 1400
  38. 1300
  39. 900
  40. 1500

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