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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 897 · 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 733 + 439? (a) 900 (b) 1300 (c) 1100
  2. 2.Best estimate of 27 × 84? (a) 24000 (b) 2400 (c) 240
  3. 3.Best estimate of 225 + 331? (a) 700 (b) 300 (c) 500
  4. 4.Best estimate of 26 × 86? (a) 2700 (b) 270 (c) 27000
  5. 5.Best estimate of 36 × 79? (a) 3200 (b) 320 (c) 32000
  6. 6.Best estimate of 36 × 82? (a) 32000 (b) 320 (c) 3200
  7. 7.Best estimate of 30 × 33? (a) 90 (b) 9000 (c) 900
  8. 8.Best estimate of 165 + 221? (a) 600 (b) 400 (c) 200
  9. 9.Best estimate of 12 × 23? (a) 200 (b) 20 (c) 2000
  10. 10.Best estimate of 13 × 58? (a) 6000 (b) 600 (c) 60
  11. 11.Best estimate of 60 × 49? (a) 30000 (b) 3000 (c) 300
  12. 12.Best estimate of 549 + 416? (a) 900 (b) 1100 (c) 700
  13. 13.Best estimate of 29 × 17? (a) 600 (b) 60 (c) 6000
  14. 14.Best estimate of 332 + 161? (a) 300 (b) 500 (c) 700
  15. 15.Best estimate of 42 × 81? (a) 320 (b) 3200 (c) 32000
  16. 16.Best estimate of 232 + 670? (a) 700 (b) 900 (c) 1100
  17. 17.Best estimate of 16 × 50? (a) 100 (b) 1000 (c) 10000
  18. 18.Best estimate of 50 × 80? (a) 40000 (b) 4000 (c) 400
  19. 19.Best estimate of 48 × 83? (a) 4000 (b) 40000 (c) 400
  20. 20.Best estimate of 153 + 376? (a) 800 (b) 400 (c) 600
  21. 21.Best estimate of 776 + 208? (a) 1200 (b) 1000 (c) 800
  22. 22.Best estimate of 424 + 449? (a) 1000 (b) 800 (c) 600
  23. 23.Best estimate of 56 × 97? (a) 60000 (b) 600 (c) 6000
  24. 24.Best estimate of 74 × 94? (a) 630 (b) 63000 (c) 6300
  25. 25.Best estimate of 36 × 44? (a) 160 (b) 1600 (c) 16000
  26. 26.Best estimate of 66 × 84? (a) 560 (b) 5600 (c) 56000
  27. 27.Best estimate of 242 + 728? (a) 900 (b) 1100 (c) 700
  28. 28.Best estimate of 36 × 86? (a) 36000 (b) 360 (c) 3600
  29. 29.Best estimate of 295 + 667? (a) 1200 (b) 800 (c) 1000
  30. 30.Best estimate of 280 + 356? (a) 700 (b) 900 (c) 500
  31. 31.Best estimate of 97 × 33? (a) 3000 (b) 30000 (c) 300
  32. 32.Best estimate of 718 + 228? (a) 1100 (b) 700 (c) 900
  33. 33.Best estimate of 16 × 27? (a) 600 (b) 6000 (c) 60
  34. 34.Best estimate of 553 + 381? (a) 1200 (b) 800 (c) 1000
  35. 35.Best estimate of 430 + 718? (a) 1300 (b) 1100 (c) 900
  36. 36.Best estimate of 557 + 324? (a) 700 (b) 900 (c) 1100
  37. 37.Best estimate of 28 × 20? (a) 600 (b) 6000 (c) 60
  38. 38.Best estimate of 81 × 40? (a) 320 (b) 32000 (c) 3200
  39. 39.Best estimate of 30 × 54? (a) 1500 (b) 150 (c) 15000
  40. 40.Best estimate of 12 × 32? (a) 300 (b) 30 (c) 3000

Answer key

  1. 1100
  2. 2400
  3. 500
  4. 2700
  5. 3200
  6. 3200
  7. 900
  8. 400
  9. 200
  10. 600
  11. 3000
  12. 900
  13. 600
  14. 500
  15. 3200
  16. 900
  17. 1000
  18. 4000
  19. 4000
  20. 600
  21. 1000
  22. 800
  23. 6000
  24. 6300
  25. 1600
  26. 5600
  27. 900
  28. 3600
  29. 1000
  30. 700
  31. 3000
  32. 900
  33. 600
  34. 1000
  35. 1100
  36. 900
  37. 600
  38. 3200
  39. 1500
  40. 300

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