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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 9 · 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 56 × 96? (a) 60000 (b) 6000 (c) 600
  2. 2.Best estimate of 508 + 822? (a) 1500 (b) 1300 (c) 1100
  3. 3.Best estimate of 23 × 26? (a) 600 (b) 6000 (c) 60
  4. 4.Best estimate of 507 + 660? (a) 1200 (b) 1000 (c) 1400
  5. 5.Best estimate of 59 × 66? (a) 42000 (b) 4200 (c) 420
  6. 6.Best estimate of 800 + 567? (a) 1200 (b) 1600 (c) 1400
  7. 7.Best estimate of 18 × 26? (a) 6000 (b) 60 (c) 600
  8. 8.Best estimate of 556 + 587? (a) 1400 (b) 1000 (c) 1200
  9. 9.Best estimate of 68 × 90? (a) 63000 (b) 6300 (c) 630
  10. 10.Best estimate of 33 × 72? (a) 21000 (b) 2100 (c) 210
  11. 11.Best estimate of 16 × 26? (a) 60 (b) 6000 (c) 600
  12. 12.Best estimate of 53 × 96? (a) 50000 (b) 5000 (c) 500
  13. 13.Best estimate of 68 × 59? (a) 420 (b) 42000 (c) 4200
  14. 14.Best estimate of 626 + 774? (a) 1200 (b) 1400 (c) 1600
  15. 15.Best estimate of 736 + 441? (a) 1100 (b) 1300 (c) 900
  16. 16.Best estimate of 79 × 86? (a) 720 (b) 7200 (c) 72000
  17. 17.Best estimate of 81 × 36? (a) 320 (b) 3200 (c) 32000
  18. 18.Best estimate of 415 + 760? (a) 1000 (b) 1400 (c) 1200
  19. 19.Best estimate of 23 × 24? (a) 4000 (b) 40 (c) 400
  20. 20.Best estimate of 76 × 20? (a) 1600 (b) 160 (c) 16000
  21. 21.Best estimate of 617 + 296? (a) 1100 (b) 900 (c) 700
  22. 22.Best estimate of 27 × 68? (a) 2100 (b) 21000 (c) 210
  23. 23.Best estimate of 49 × 76? (a) 4000 (b) 400 (c) 40000
  24. 24.Best estimate of 37 × 91? (a) 36000 (b) 3600 (c) 360
  25. 25.Best estimate of 67 × 17? (a) 14000 (b) 1400 (c) 140
  26. 26.Best estimate of 16 × 23? (a) 4000 (b) 40 (c) 400
  27. 27.Best estimate of 315 + 857? (a) 1200 (b) 1400 (c) 1000
  28. 28.Best estimate of 737 + 400? (a) 1100 (b) 1300 (c) 900
  29. 29.Best estimate of 63 × 36? (a) 24000 (b) 240 (c) 2400
  30. 30.Best estimate of 94 × 12? (a) 900 (b) 9000 (c) 90
  31. 31.Best estimate of 200 + 128? (a) 500 (b) 100 (c) 300
  32. 32.Best estimate of 356 + 455? (a) 1100 (b) 900 (c) 700
  33. 33.Best estimate of 207 + 297? (a) 500 (b) 700 (c) 300
  34. 34.Best estimate of 336 + 453? (a) 1000 (b) 600 (c) 800
  35. 35.Best estimate of 92 × 27? (a) 2700 (b) 270 (c) 27000
  36. 36.Best estimate of 834 + 448? (a) 1000 (b) 1400 (c) 1200
  37. 37.Best estimate of 444 + 434? (a) 1000 (b) 600 (c) 800
  38. 38.Best estimate of 93 × 32? (a) 27000 (b) 2700 (c) 270
  39. 39.Best estimate of 794 + 442? (a) 1200 (b) 1400 (c) 1000
  40. 40.Best estimate of 870 + 474? (a) 1400 (b) 1600 (c) 1200

Answer key

  1. 6000
  2. 1300
  3. 600
  4. 1200
  5. 4200
  6. 1400
  7. 600
  8. 1200
  9. 6300
  10. 2100
  11. 600
  12. 5000
  13. 4200
  14. 1400
  15. 1100
  16. 7200
  17. 3200
  18. 1200
  19. 400
  20. 1600
  21. 900
  22. 2100
  23. 4000
  24. 3600
  25. 1400
  26. 400
  27. 1200
  28. 1100
  29. 2400
  30. 900
  31. 300
  32. 900
  33. 500
  34. 800
  35. 2700
  36. 1200
  37. 800
  38. 2700
  39. 1200
  40. 1400

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