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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 357 · 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 57 × 76? (a) 4800 (b) 48000 (c) 480
  2. 2.Best estimate of 27 × 41? (a) 1200 (b) 12000 (c) 120
  3. 3.Best estimate of 277 + 379? (a) 500 (b) 700 (c) 900
  4. 4.Best estimate of 63 × 12? (a) 60 (b) 6000 (c) 600
  5. 5.Best estimate of 694 + 266? (a) 800 (b) 1200 (c) 1000
  6. 6.Best estimate of 269 + 593? (a) 900 (b) 700 (c) 1100
  7. 7.Best estimate of 21 × 44? (a) 80 (b) 800 (c) 8000
  8. 8.Best estimate of 59 × 59? (a) 36000 (b) 360 (c) 3600
  9. 9.Best estimate of 152 + 535? (a) 500 (b) 900 (c) 700
  10. 10.Best estimate of 486 + 139? (a) 800 (b) 600 (c) 400
  11. 11.Best estimate of 44 × 73? (a) 28000 (b) 280 (c) 2800
  12. 12.Best estimate of 97 × 66? (a) 70000 (b) 700 (c) 7000
  13. 13.Best estimate of 12 × 69? (a) 700 (b) 7000 (c) 70
  14. 14.Best estimate of 14 × 54? (a) 50 (b) 500 (c) 5000
  15. 15.Best estimate of 727 + 261? (a) 1200 (b) 1000 (c) 800
  16. 16.Best estimate of 60 × 89? (a) 540 (b) 5400 (c) 54000
  17. 17.Best estimate of 576 + 579? (a) 1400 (b) 1200 (c) 1000
  18. 18.Best estimate of 86 × 33? (a) 27000 (b) 2700 (c) 270
  19. 19.Best estimate of 77 × 33? (a) 240 (b) 24000 (c) 2400
  20. 20.Best estimate of 626 + 385? (a) 1000 (b) 1200 (c) 800
  21. 21.Best estimate of 563 + 133? (a) 500 (b) 900 (c) 700
  22. 22.Best estimate of 97 × 31? (a) 30000 (b) 300 (c) 3000
  23. 23.Best estimate of 162 + 148? (a) 100 (b) 300 (c) 500
  24. 24.Best estimate of 22 × 36? (a) 80 (b) 800 (c) 8000
  25. 25.Best estimate of 89 × 27? (a) 2700 (b) 27000 (c) 270
  26. 26.Best estimate of 268 + 195? (a) 700 (b) 500 (c) 300
  27. 27.Best estimate of 74 × 96? (a) 7000 (b) 70000 (c) 700
  28. 28.Best estimate of 276 + 671? (a) 800 (b) 1200 (c) 1000
  29. 29.Best estimate of 189 + 315? (a) 500 (b) 300 (c) 700
  30. 30.Best estimate of 816 + 371? (a) 1200 (b) 1400 (c) 1000
  31. 31.Best estimate of 71 × 12? (a) 700 (b) 70 (c) 7000
  32. 32.Best estimate of 675 + 590? (a) 1100 (b) 1300 (c) 1500
  33. 33.Best estimate of 28 × 30? (a) 900 (b) 9000 (c) 90
  34. 34.Best estimate of 629 + 292? (a) 700 (b) 1100 (c) 900
  35. 35.Best estimate of 799 + 183? (a) 800 (b) 1200 (c) 1000
  36. 36.Best estimate of 92 × 98? (a) 900 (b) 9000 (c) 90000
  37. 37.Best estimate of 76 × 48? (a) 4000 (b) 400 (c) 40000
  38. 38.Best estimate of 76 × 34? (a) 24000 (b) 240 (c) 2400
  39. 39.Best estimate of 87 × 31? (a) 270 (b) 2700 (c) 27000
  40. 40.Best estimate of 36 × 63? (a) 24000 (b) 240 (c) 2400

Answer key

  1. 4800
  2. 1200
  3. 700
  4. 600
  5. 1000
  6. 900
  7. 800
  8. 3600
  9. 700
  10. 600
  11. 2800
  12. 7000
  13. 700
  14. 500
  15. 1000
  16. 5400
  17. 1200
  18. 2700
  19. 2400
  20. 1000
  21. 700
  22. 3000
  23. 300
  24. 800
  25. 2700
  26. 500
  27. 7000
  28. 1000
  29. 500
  30. 1200
  31. 700
  32. 1300
  33. 900
  34. 900
  35. 1000
  36. 9000
  37. 4000
  38. 2400
  39. 2700
  40. 2400

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