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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 204 · 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 27 × 86? (a) 270 (b) 27000 (c) 2700
  2. 2.Best estimate of 371 + 275? (a) 500 (b) 900 (c) 700
  3. 3.Best estimate of 64 × 69? (a) 42000 (b) 420 (c) 4200
  4. 4.Best estimate of 98 × 69? (a) 700 (b) 70000 (c) 7000
  5. 5.Best estimate of 31 × 49? (a) 150 (b) 15000 (c) 1500
  6. 6.Best estimate of 188 + 803? (a) 1200 (b) 1000 (c) 800
  7. 7.Best estimate of 67 × 76? (a) 5600 (b) 560 (c) 56000
  8. 8.Best estimate of 692 + 263? (a) 1000 (b) 800 (c) 1200
  9. 9.Best estimate of 87 × 28? (a) 270 (b) 2700 (c) 27000
  10. 10.Best estimate of 406 + 868? (a) 1100 (b) 1300 (c) 1500
  11. 11.Best estimate of 56 × 77? (a) 48000 (b) 4800 (c) 480
  12. 12.Best estimate of 169 + 415? (a) 600 (b) 400 (c) 800
  13. 13.Best estimate of 33 × 12? (a) 300 (b) 3000 (c) 30
  14. 14.Best estimate of 19 × 26? (a) 600 (b) 6000 (c) 60
  15. 15.Best estimate of 98 × 57? (a) 60000 (b) 600 (c) 6000
  16. 16.Best estimate of 47 × 34? (a) 1500 (b) 150 (c) 15000
  17. 17.Best estimate of 97 × 53? (a) 500 (b) 5000 (c) 50000
  18. 18.Best estimate of 93 × 77? (a) 720 (b) 72000 (c) 7200
  19. 19.Best estimate of 293 + 128? (a) 400 (b) 200 (c) 600
  20. 20.Best estimate of 869 + 406? (a) 1300 (b) 1100 (c) 1500
  21. 21.Best estimate of 39 × 13? (a) 40 (b) 400 (c) 4000
  22. 22.Best estimate of 800 + 394? (a) 1000 (b) 1200 (c) 1400
  23. 23.Best estimate of 37 × 86? (a) 3600 (b) 36000 (c) 360
  24. 24.Best estimate of 436 + 634? (a) 1200 (b) 800 (c) 1000
  25. 25.Best estimate of 26 × 40? (a) 12000 (b) 120 (c) 1200
  26. 26.Best estimate of 817 + 292? (a) 900 (b) 1300 (c) 1100
  27. 27.Best estimate of 152 + 810? (a) 1200 (b) 1000 (c) 800
  28. 28.Best estimate of 23 × 92? (a) 180 (b) 1800 (c) 18000
  29. 29.Best estimate of 18 × 32? (a) 6000 (b) 60 (c) 600
  30. 30.Best estimate of 561 + 571? (a) 1000 (b) 1200 (c) 1400
  31. 31.Best estimate of 580 + 440? (a) 1000 (b) 1200 (c) 800
  32. 32.Best estimate of 36 × 81? (a) 32000 (b) 3200 (c) 320
  33. 33.Best estimate of 66 × 16? (a) 1400 (b) 14000 (c) 140
  34. 34.Best estimate of 91 × 26? (a) 2700 (b) 270 (c) 27000
  35. 35.Best estimate of 13 × 56? (a) 6000 (b) 600 (c) 60
  36. 36.Best estimate of 295 + 289? (a) 400 (b) 800 (c) 600
  37. 37.Best estimate of 636 + 289? (a) 900 (b) 700 (c) 1100
  38. 38.Best estimate of 61 × 68? (a) 4200 (b) 420 (c) 42000
  39. 39.Best estimate of 82 × 57? (a) 480 (b) 4800 (c) 48000
  40. 40.Best estimate of 77 × 92? (a) 720 (b) 7200 (c) 72000

Answer key

  1. 2700
  2. 700
  3. 4200
  4. 7000
  5. 1500
  6. 1000
  7. 5600
  8. 1000
  9. 2700
  10. 1300
  11. 4800
  12. 600
  13. 300
  14. 600
  15. 6000
  16. 1500
  17. 5000
  18. 7200
  19. 400
  20. 1300
  21. 400
  22. 1200
  23. 3600
  24. 1000
  25. 1200
  26. 1100
  27. 1000
  28. 1800
  29. 600
  30. 1200
  31. 1000
  32. 3200
  33. 1400
  34. 2700
  35. 600
  36. 600
  37. 900
  38. 4200
  39. 4800
  40. 7200

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