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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 439 · 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 26 × 89? (a) 270 (b) 2700 (c) 27000
  2. 2.Best estimate of 96 × 17? (a) 200 (b) 2000 (c) 20000
  3. 3.Best estimate of 16 × 16? (a) 400 (b) 4000 (c) 40
  4. 4.Best estimate of 272 + 771? (a) 1300 (b) 900 (c) 1100
  5. 5.Best estimate of 225 + 351? (a) 800 (b) 600 (c) 400
  6. 6.Best estimate of 13 × 82? (a) 800 (b) 80 (c) 8000
  7. 7.Best estimate of 36 × 93? (a) 3600 (b) 360 (c) 36000
  8. 8.Best estimate of 854 + 164? (a) 1300 (b) 1100 (c) 900
  9. 9.Best estimate of 540 + 769? (a) 1100 (b) 1300 (c) 1500
  10. 10.Best estimate of 29 × 74? (a) 21000 (b) 210 (c) 2100
  11. 11.Best estimate of 13 × 97? (a) 10000 (b) 1000 (c) 100
  12. 12.Best estimate of 21 × 70? (a) 1400 (b) 14000 (c) 140
  13. 13.Best estimate of 42 × 57? (a) 24000 (b) 2400 (c) 240
  14. 14.Best estimate of 56 × 20? (a) 120 (b) 1200 (c) 12000
  15. 15.Best estimate of 874 + 710? (a) 1400 (b) 1600 (c) 1800
  16. 16.Best estimate of 94 × 82? (a) 720 (b) 72000 (c) 7200
  17. 17.Best estimate of 406 + 167? (a) 800 (b) 600 (c) 400
  18. 18.Best estimate of 687 + 226? (a) 900 (b) 1100 (c) 700
  19. 19.Best estimate of 73 × 62? (a) 4200 (b) 42000 (c) 420
  20. 20.Best estimate of 73 × 50? (a) 3500 (b) 35000 (c) 350
  21. 21.Best estimate of 12 × 48? (a) 5000 (b) 500 (c) 50
  22. 22.Best estimate of 215 + 477? (a) 700 (b) 500 (c) 900
  23. 23.Best estimate of 26 × 71? (a) 2100 (b) 21000 (c) 210
  24. 24.Best estimate of 651 + 820? (a) 1700 (b) 1500 (c) 1300
  25. 25.Best estimate of 46 × 20? (a) 1000 (b) 100 (c) 10000
  26. 26.Best estimate of 57 × 84? (a) 480 (b) 4800 (c) 48000
  27. 27.Best estimate of 26 × 16? (a) 60 (b) 600 (c) 6000
  28. 28.Best estimate of 814 + 191? (a) 800 (b) 1200 (c) 1000
  29. 29.Best estimate of 92 × 73? (a) 6300 (b) 630 (c) 63000
  30. 30.Best estimate of 92 × 61? (a) 54000 (b) 5400 (c) 540
  31. 31.Best estimate of 49 × 26? (a) 15000 (b) 1500 (c) 150
  32. 32.Best estimate of 86 × 18? (a) 1800 (b) 18000 (c) 180
  33. 33.Best estimate of 43 × 27? (a) 120 (b) 12000 (c) 1200
  34. 34.Best estimate of 81 × 28? (a) 240 (b) 2400 (c) 24000
  35. 35.Best estimate of 311 + 389? (a) 500 (b) 700 (c) 900
  36. 36.Best estimate of 30 × 62? (a) 1800 (b) 18000 (c) 180
  37. 37.Best estimate of 32 × 23? (a) 60 (b) 6000 (c) 600
  38. 38.Best estimate of 145 + 225? (a) 500 (b) 100 (c) 300
  39. 39.Best estimate of 535 + 288? (a) 600 (b) 1000 (c) 800
  40. 40.Best estimate of 36 × 86? (a) 3600 (b) 360 (c) 36000

Answer key

  1. 2700
  2. 2000
  3. 400
  4. 1100
  5. 600
  6. 800
  7. 3600
  8. 1100
  9. 1300
  10. 2100
  11. 1000
  12. 1400
  13. 2400
  14. 1200
  15. 1600
  16. 7200
  17. 600
  18. 900
  19. 4200
  20. 3500
  21. 500
  22. 700
  23. 2100
  24. 1500
  25. 1000
  26. 4800
  27. 600
  28. 1000
  29. 6300
  30. 5400
  31. 1500
  32. 1800
  33. 1200
  34. 2400
  35. 700
  36. 1800
  37. 600
  38. 300
  39. 800
  40. 3600

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