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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 192 · 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 × 80? (a) 1600 (b) 160 (c) 16000
  2. 2.Best estimate of 14 × 29? (a) 3000 (b) 300 (c) 30
  3. 3.Best estimate of 44 × 96? (a) 40000 (b) 4000 (c) 400
  4. 4.Best estimate of 322 + 741? (a) 1200 (b) 800 (c) 1000
  5. 5.Best estimate of 54 × 38? (a) 200 (b) 2000 (c) 20000
  6. 6.Best estimate of 96 × 92? (a) 900 (b) 9000 (c) 90000
  7. 7.Best estimate of 17 × 88? (a) 18000 (b) 180 (c) 1800
  8. 8.Best estimate of 79 × 96? (a) 8000 (b) 80000 (c) 800
  9. 9.Best estimate of 96 × 56? (a) 6000 (b) 600 (c) 60000
  10. 10.Best estimate of 54 × 17? (a) 10000 (b) 100 (c) 1000
  11. 11.Best estimate of 757 + 479? (a) 1300 (b) 1500 (c) 1100
  12. 12.Best estimate of 72 × 36? (a) 2800 (b) 28000 (c) 280
  13. 13.Best estimate of 77 × 12? (a) 800 (b) 80 (c) 8000
  14. 14.Best estimate of 492 + 761? (a) 1300 (b) 1500 (c) 1100
  15. 15.Best estimate of 89 × 37? (a) 36000 (b) 360 (c) 3600
  16. 16.Best estimate of 216 + 204? (a) 400 (b) 200 (c) 600
  17. 17.Best estimate of 768 + 296? (a) 900 (b) 1300 (c) 1100
  18. 18.Best estimate of 63 × 27? (a) 1800 (b) 18000 (c) 180
  19. 19.Best estimate of 661 + 841? (a) 1700 (b) 1500 (c) 1300
  20. 20.Best estimate of 76 × 20? (a) 1600 (b) 160 (c) 16000
  21. 21.Best estimate of 289 + 351? (a) 700 (b) 500 (c) 900
  22. 22.Best estimate of 661 + 366? (a) 1300 (b) 1100 (c) 900
  23. 23.Best estimate of 59 × 13? (a) 600 (b) 6000 (c) 60
  24. 24.Best estimate of 76 × 82? (a) 6400 (b) 64000 (c) 640
  25. 25.Best estimate of 34 × 30? (a) 9000 (b) 900 (c) 90
  26. 26.Best estimate of 96 × 96? (a) 10000 (b) 1000 (c) 100000
  27. 27.Best estimate of 336 + 513? (a) 600 (b) 1000 (c) 800
  28. 28.Best estimate of 646 + 516? (a) 1300 (b) 1100 (c) 900
  29. 29.Best estimate of 57 × 80? (a) 4800 (b) 480 (c) 48000
  30. 30.Best estimate of 643 + 139? (a) 500 (b) 700 (c) 900
  31. 31.Best estimate of 82 × 59? (a) 480 (b) 48000 (c) 4800
  32. 32.Best estimate of 96 × 12? (a) 100 (b) 10000 (c) 1000
  33. 33.Best estimate of 43 × 12? (a) 4000 (b) 40 (c) 400
  34. 34.Best estimate of 84 × 42? (a) 32000 (b) 3200 (c) 320
  35. 35.Best estimate of 470 + 331? (a) 1000 (b) 600 (c) 800
  36. 36.Best estimate of 77 × 76? (a) 6400 (b) 64000 (c) 640
  37. 37.Best estimate of 211 + 699? (a) 1100 (b) 900 (c) 700
  38. 38.Best estimate of 22 × 23? (a) 40 (b) 4000 (c) 400
  39. 39.Best estimate of 80 × 16? (a) 1600 (b) 160 (c) 16000
  40. 40.Best estimate of 568 + 128? (a) 900 (b) 700 (c) 500

Answer key

  1. 1600
  2. 300
  3. 4000
  4. 1000
  5. 2000
  6. 9000
  7. 1800
  8. 8000
  9. 6000
  10. 1000
  11. 1300
  12. 2800
  13. 800
  14. 1300
  15. 3600
  16. 400
  17. 1100
  18. 1800
  19. 1500
  20. 1600
  21. 700
  22. 1100
  23. 600
  24. 6400
  25. 900
  26. 10000
  27. 800
  28. 1100
  29. 4800
  30. 700
  31. 4800
  32. 1000
  33. 400
  34. 3200
  35. 800
  36. 6400
  37. 900
  38. 400
  39. 1600
  40. 700

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