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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 748 · 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 96 × 98? (a) 10000 (b) 1000 (c) 100000
  2. 2.Best estimate of 691 + 254? (a) 1200 (b) 1000 (c) 800
  3. 3.Best estimate of 574 + 161? (a) 800 (b) 600 (c) 1000
  4. 4.Best estimate of 539 + 826? (a) 1500 (b) 1100 (c) 1300
  5. 5.Best estimate of 46 × 56? (a) 300 (b) 30000 (c) 3000
  6. 6.Best estimate of 746 + 809? (a) 1500 (b) 1300 (c) 1700
  7. 7.Best estimate of 47 × 21? (a) 1000 (b) 100 (c) 10000
  8. 8.Best estimate of 545 + 254? (a) 800 (b) 600 (c) 1000
  9. 9.Best estimate of 568 + 331? (a) 700 (b) 900 (c) 1100
  10. 10.Best estimate of 784 + 523? (a) 1100 (b) 1500 (c) 1300
  11. 11.Best estimate of 71 × 96? (a) 70000 (b) 700 (c) 7000
  12. 12.Best estimate of 206 + 351? (a) 400 (b) 800 (c) 600
  13. 13.Best estimate of 52 × 64? (a) 300 (b) 30000 (c) 3000
  14. 14.Best estimate of 771 + 742? (a) 1500 (b) 1300 (c) 1700
  15. 15.Best estimate of 28 × 71? (a) 21000 (b) 210 (c) 2100
  16. 16.Best estimate of 223 + 272? (a) 700 (b) 300 (c) 500
  17. 17.Best estimate of 661 + 771? (a) 1700 (b) 1500 (c) 1300
  18. 18.Best estimate of 21 × 28? (a) 6000 (b) 600 (c) 60
  19. 19.Best estimate of 66 × 83? (a) 56000 (b) 5600 (c) 560
  20. 20.Best estimate of 53 × 72? (a) 35000 (b) 350 (c) 3500
  21. 21.Best estimate of 76 × 93? (a) 72000 (b) 720 (c) 7200
  22. 22.Best estimate of 313 + 340? (a) 800 (b) 600 (c) 400
  23. 23.Best estimate of 545 + 669? (a) 1000 (b) 1400 (c) 1200
  24. 24.Best estimate of 813 + 185? (a) 1200 (b) 800 (c) 1000
  25. 25.Best estimate of 308 + 355? (a) 700 (b) 500 (c) 900
  26. 26.Best estimate of 604 + 664? (a) 1500 (b) 1300 (c) 1100
  27. 27.Best estimate of 811 + 637? (a) 1600 (b) 1400 (c) 1200
  28. 28.Best estimate of 743 + 490? (a) 1200 (b) 1400 (c) 1000
  29. 29.Best estimate of 79 × 36? (a) 3200 (b) 32000 (c) 320
  30. 30.Best estimate of 28 × 86? (a) 27000 (b) 270 (c) 2700
  31. 31.Best estimate of 16 × 71? (a) 1400 (b) 14000 (c) 140
  32. 32.Best estimate of 598 + 363? (a) 1200 (b) 1000 (c) 800
  33. 33.Best estimate of 866 + 821? (a) 1700 (b) 1500 (c) 1900
  34. 34.Best estimate of 37 × 46? (a) 2000 (b) 200 (c) 20000
  35. 35.Best estimate of 61 × 26? (a) 18000 (b) 1800 (c) 180
  36. 36.Best estimate of 335 + 376? (a) 900 (b) 700 (c) 500
  37. 37.Best estimate of 77 × 39? (a) 320 (b) 3200 (c) 32000
  38. 38.Best estimate of 306 + 623? (a) 900 (b) 700 (c) 1100
  39. 39.Best estimate of 83 × 70? (a) 5600 (b) 56000 (c) 560
  40. 40.Best estimate of 26 × 28? (a) 900 (b) 90 (c) 9000

Answer key

  1. 10000
  2. 1000
  3. 800
  4. 1300
  5. 3000
  6. 1500
  7. 1000
  8. 800
  9. 900
  10. 1300
  11. 7000
  12. 600
  13. 3000
  14. 1500
  15. 2100
  16. 500
  17. 1500
  18. 600
  19. 5600
  20. 3500
  21. 7200
  22. 600
  23. 1200
  24. 1000
  25. 700
  26. 1300
  27. 1400
  28. 1200
  29. 3200
  30. 2700
  31. 1400
  32. 1000
  33. 1700
  34. 2000
  35. 1800
  36. 700
  37. 3200
  38. 900
  39. 5600
  40. 900

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