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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 992 · 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 17 × 56? (a) 12000 (b) 120 (c) 1200
  2. 2.Best estimate of 272 + 441? (a) 700 (b) 900 (c) 500
  3. 3.Best estimate of 222 + 569? (a) 600 (b) 1000 (c) 800
  4. 4.Best estimate of 86 × 20? (a) 1800 (b) 18000 (c) 180
  5. 5.Best estimate of 49 × 57? (a) 3000 (b) 300 (c) 30000
  6. 6.Best estimate of 98 × 22? (a) 20000 (b) 200 (c) 2000
  7. 7.Best estimate of 215 + 737? (a) 700 (b) 1100 (c) 900
  8. 8.Best estimate of 36 × 98? (a) 40000 (b) 400 (c) 4000
  9. 9.Best estimate of 638 + 197? (a) 800 (b) 1000 (c) 600
  10. 10.Best estimate of 288 + 647? (a) 900 (b) 1100 (c) 700
  11. 11.Best estimate of 76 × 29? (a) 240 (b) 2400 (c) 24000
  12. 12.Best estimate of 81 × 94? (a) 72000 (b) 7200 (c) 720
  13. 13.Best estimate of 48 × 91? (a) 4500 (b) 450 (c) 45000
  14. 14.Best estimate of 518 + 378? (a) 1100 (b) 700 (c) 900
  15. 15.Best estimate of 561 + 503? (a) 1100 (b) 1300 (c) 900
  16. 16.Best estimate of 98 × 17? (a) 200 (b) 2000 (c) 20000
  17. 17.Best estimate of 399 + 554? (a) 1200 (b) 1000 (c) 800
  18. 18.Best estimate of 702 + 539? (a) 1400 (b) 1000 (c) 1200
  19. 19.Best estimate of 688 + 557? (a) 1500 (b) 1300 (c) 1100
  20. 20.Best estimate of 591 + 872? (a) 1500 (b) 1700 (c) 1300
  21. 21.Best estimate of 733 + 743? (a) 1200 (b) 1400 (c) 1600
  22. 22.Best estimate of 34 × 29? (a) 900 (b) 90 (c) 9000
  23. 23.Best estimate of 78 × 97? (a) 80000 (b) 800 (c) 8000
  24. 24.Best estimate of 675 + 211? (a) 900 (b) 1100 (c) 700
  25. 25.Best estimate of 71 × 19? (a) 14000 (b) 1400 (c) 140
  26. 26.Best estimate of 671 + 858? (a) 1600 (b) 1800 (c) 1400
  27. 27.Best estimate of 432 + 212? (a) 600 (b) 400 (c) 800
  28. 28.Best estimate of 96 × 19? (a) 200 (b) 2000 (c) 20000
  29. 29.Best estimate of 267 + 208? (a) 500 (b) 300 (c) 700
  30. 30.Best estimate of 789 + 530? (a) 1100 (b) 1500 (c) 1300
  31. 31.Best estimate of 73 × 54? (a) 350 (b) 3500 (c) 35000
  32. 32.Best estimate of 39 × 19? (a) 800 (b) 8000 (c) 80
  33. 33.Best estimate of 296 + 265? (a) 400 (b) 600 (c) 800
  34. 34.Best estimate of 26 × 16? (a) 600 (b) 60 (c) 6000
  35. 35.Best estimate of 81 × 88? (a) 7200 (b) 72000 (c) 720
  36. 36.Best estimate of 731 + 611? (a) 1300 (b) 1100 (c) 1500
  37. 37.Best estimate of 80 × 76? (a) 6400 (b) 640 (c) 64000
  38. 38.Best estimate of 46 × 27? (a) 15000 (b) 150 (c) 1500
  39. 39.Best estimate of 48 × 76? (a) 4000 (b) 400 (c) 40000
  40. 40.Best estimate of 206 + 254? (a) 300 (b) 700 (c) 500

Answer key

  1. 1200
  2. 700
  3. 800
  4. 1800
  5. 3000
  6. 2000
  7. 900
  8. 4000
  9. 800
  10. 900
  11. 2400
  12. 7200
  13. 4500
  14. 900
  15. 1100
  16. 2000
  17. 1000
  18. 1200
  19. 1300
  20. 1500
  21. 1400
  22. 900
  23. 8000
  24. 900
  25. 1400
  26. 1600
  27. 600
  28. 2000
  29. 500
  30. 1300
  31. 3500
  32. 800
  33. 600
  34. 600
  35. 7200
  36. 1300
  37. 6400
  38. 1500
  39. 4000
  40. 500

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