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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 885 · 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 40 × 36? (a) 1600 (b) 16000 (c) 160
  2. 2.Best estimate of 467 + 200? (a) 700 (b) 500 (c) 900
  3. 3.Best estimate of 618 + 780? (a) 1400 (b) 1200 (c) 1600
  4. 4.Best estimate of 856 + 551? (a) 1700 (b) 1300 (c) 1500
  5. 5.Best estimate of 714 + 251? (a) 1200 (b) 800 (c) 1000
  6. 6.Best estimate of 98 × 24? (a) 200 (b) 2000 (c) 20000
  7. 7.Best estimate of 92 × 34? (a) 2700 (b) 270 (c) 27000
  8. 8.Best estimate of 840 + 427? (a) 1400 (b) 1200 (c) 1000
  9. 9.Best estimate of 48 × 17? (a) 10000 (b) 100 (c) 1000
  10. 10.Best estimate of 854 + 440? (a) 1300 (b) 1500 (c) 1100
  11. 11.Best estimate of 89 × 72? (a) 630 (b) 63000 (c) 6300
  12. 12.Best estimate of 16 × 73? (a) 1400 (b) 140 (c) 14000
  13. 13.Best estimate of 725 + 672? (a) 1200 (b) 1600 (c) 1400
  14. 14.Best estimate of 365 + 703? (a) 1300 (b) 1100 (c) 900
  15. 15.Best estimate of 814 + 519? (a) 1100 (b) 1500 (c) 1300
  16. 16.Best estimate of 779 + 337? (a) 900 (b) 1300 (c) 1100
  17. 17.Best estimate of 876 + 669? (a) 1800 (b) 1400 (c) 1600
  18. 18.Best estimate of 61 × 41? (a) 24000 (b) 2400 (c) 240
  19. 19.Best estimate of 34 × 66? (a) 21000 (b) 2100 (c) 210
  20. 20.Best estimate of 78 × 76? (a) 6400 (b) 640 (c) 64000
  21. 21.Best estimate of 27 × 90? (a) 2700 (b) 27000 (c) 270
  22. 22.Best estimate of 96 × 40? (a) 40000 (b) 4000 (c) 400
  23. 23.Best estimate of 33 × 74? (a) 2100 (b) 21000 (c) 210
  24. 24.Best estimate of 48 × 59? (a) 30000 (b) 3000 (c) 300
  25. 25.Best estimate of 788 + 261? (a) 900 (b) 1300 (c) 1100
  26. 26.Best estimate of 52 × 13? (a) 5000 (b) 500 (c) 50
  27. 27.Best estimate of 860 + 812? (a) 1900 (b) 1700 (c) 1500
  28. 28.Best estimate of 230 + 451? (a) 500 (b) 700 (c) 900
  29. 29.Best estimate of 442 + 627? (a) 1200 (b) 1000 (c) 800
  30. 30.Best estimate of 12 × 26? (a) 3000 (b) 30 (c) 300
  31. 31.Best estimate of 323 + 606? (a) 1100 (b) 700 (c) 900
  32. 32.Best estimate of 455 + 467? (a) 800 (b) 1200 (c) 1000
  33. 33.Best estimate of 22 × 83? (a) 16000 (b) 1600 (c) 160
  34. 34.Best estimate of 92 × 19? (a) 180 (b) 1800 (c) 18000
  35. 35.Best estimate of 536 + 709? (a) 1200 (b) 1000 (c) 1400
  36. 36.Best estimate of 330 + 463? (a) 600 (b) 800 (c) 1000
  37. 37.Best estimate of 14 × 37? (a) 40 (b) 4000 (c) 400
  38. 38.Best estimate of 260 + 184? (a) 500 (b) 700 (c) 300
  39. 39.Best estimate of 54 × 19? (a) 1000 (b) 100 (c) 10000
  40. 40.Best estimate of 376 + 856? (a) 1300 (b) 1500 (c) 1100

Answer key

  1. 1600
  2. 700
  3. 1400
  4. 1500
  5. 1000
  6. 2000
  7. 2700
  8. 1200
  9. 1000
  10. 1300
  11. 6300
  12. 1400
  13. 1400
  14. 1100
  15. 1300
  16. 1100
  17. 1600
  18. 2400
  19. 2100
  20. 6400
  21. 2700
  22. 4000
  23. 2100
  24. 3000
  25. 1100
  26. 500
  27. 1700
  28. 700
  29. 1000
  30. 300
  31. 900
  32. 1000
  33. 1600
  34. 1800
  35. 1200
  36. 800
  37. 400
  38. 500
  39. 1000
  40. 1300

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