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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 988 · 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 91 × 43? (a) 3600 (b) 36000 (c) 360
  2. 2.Best estimate of 880 + 703? (a) 1400 (b) 1800 (c) 1600
  3. 3.Best estimate of 271 + 140? (a) 200 (b) 400 (c) 600
  4. 4.Best estimate of 492 + 569? (a) 1300 (b) 1100 (c) 900
  5. 5.Best estimate of 34 × 47? (a) 150 (b) 15000 (c) 1500
  6. 6.Best estimate of 19 × 88? (a) 18000 (b) 1800 (c) 180
  7. 7.Best estimate of 84 × 34? (a) 2400 (b) 24000 (c) 240
  8. 8.Best estimate of 73 × 69? (a) 490 (b) 4900 (c) 49000
  9. 9.Best estimate of 260 + 745? (a) 1200 (b) 800 (c) 1000
  10. 10.Best estimate of 28 × 96? (a) 30000 (b) 3000 (c) 300
  11. 11.Best estimate of 484 + 437? (a) 900 (b) 1100 (c) 700
  12. 12.Best estimate of 373 + 836? (a) 1200 (b) 1400 (c) 1000
  13. 13.Best estimate of 88 × 30? (a) 2700 (b) 27000 (c) 270
  14. 14.Best estimate of 806 + 770? (a) 1600 (b) 1400 (c) 1800
  15. 15.Best estimate of 94 × 97? (a) 90000 (b) 9000 (c) 900
  16. 16.Best estimate of 551 + 186? (a) 800 (b) 1000 (c) 600
  17. 17.Best estimate of 532 + 219? (a) 500 (b) 700 (c) 900
  18. 18.Best estimate of 12 × 96? (a) 100 (b) 1000 (c) 10000
  19. 19.Best estimate of 143 + 660? (a) 1000 (b) 800 (c) 600
  20. 20.Best estimate of 238 + 692? (a) 900 (b) 1100 (c) 700
  21. 21.Best estimate of 64 × 82? (a) 4800 (b) 480 (c) 48000
  22. 22.Best estimate of 251 + 482? (a) 800 (b) 600 (c) 1000
  23. 23.Best estimate of 621 + 587? (a) 1400 (b) 1200 (c) 1000
  24. 24.Best estimate of 20 × 47? (a) 1000 (b) 100 (c) 10000
  25. 25.Best estimate of 71 × 26? (a) 2100 (b) 210 (c) 21000
  26. 26.Best estimate of 624 + 300? (a) 1100 (b) 700 (c) 900
  27. 27.Best estimate of 619 + 544? (a) 1300 (b) 900 (c) 1100
  28. 28.Best estimate of 490 + 449? (a) 1100 (b) 700 (c) 900
  29. 29.Best estimate of 699 + 129? (a) 1000 (b) 800 (c) 600
  30. 30.Best estimate of 82 × 71? (a) 560 (b) 56000 (c) 5600
  31. 31.Best estimate of 13 × 93? (a) 900 (b) 90 (c) 9000
  32. 32.Best estimate of 527 + 358? (a) 1100 (b) 900 (c) 700
  33. 33.Best estimate of 67 × 78? (a) 56000 (b) 560 (c) 5600
  34. 34.Best estimate of 594 + 832? (a) 1600 (b) 1400 (c) 1200
  35. 35.Best estimate of 60 × 74? (a) 420 (b) 42000 (c) 4200
  36. 36.Best estimate of 755 + 564? (a) 1200 (b) 1600 (c) 1400
  37. 37.Best estimate of 73 × 19? (a) 140 (b) 1400 (c) 14000
  38. 38.Best estimate of 59 × 60? (a) 3600 (b) 36000 (c) 360
  39. 39.Best estimate of 314 + 610? (a) 900 (b) 700 (c) 1100
  40. 40.Best estimate of 140 + 819? (a) 1100 (b) 700 (c) 900

Answer key

  1. 3600
  2. 1600
  3. 400
  4. 1100
  5. 1500
  6. 1800
  7. 2400
  8. 4900
  9. 1000
  10. 3000
  11. 900
  12. 1200
  13. 2700
  14. 1600
  15. 9000
  16. 800
  17. 700
  18. 1000
  19. 800
  20. 900
  21. 4800
  22. 800
  23. 1200
  24. 1000
  25. 2100
  26. 900
  27. 1100
  28. 900
  29. 800
  30. 5600
  31. 900
  32. 900
  33. 5600
  34. 1400
  35. 4200
  36. 1400
  37. 1400
  38. 3600
  39. 900
  40. 900

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