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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 548 · 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 561 + 428? (a) 1000 (b) 1200 (c) 800
  2. 2.Best estimate of 46 × 33? (a) 150 (b) 15000 (c) 1500
  3. 3.Best estimate of 31 × 12? (a) 30 (b) 300 (c) 3000
  4. 4.Best estimate of 37 × 24? (a) 800 (b) 8000 (c) 80
  5. 5.Best estimate of 60 × 27? (a) 180 (b) 18000 (c) 1800
  6. 6.Best estimate of 79 × 30? (a) 24000 (b) 240 (c) 2400
  7. 7.Best estimate of 769 + 848? (a) 1400 (b) 1600 (c) 1800
  8. 8.Best estimate of 46 × 57? (a) 30000 (b) 3000 (c) 300
  9. 9.Best estimate of 66 × 50? (a) 3500 (b) 35000 (c) 350
  10. 10.Best estimate of 61 × 32? (a) 18000 (b) 1800 (c) 180
  11. 11.Best estimate of 31 × 92? (a) 2700 (b) 27000 (c) 270
  12. 12.Best estimate of 19 × 42? (a) 80 (b) 800 (c) 8000
  13. 13.Best estimate of 741 + 628? (a) 1300 (b) 1500 (c) 1100
  14. 14.Best estimate of 352 + 830? (a) 1400 (b) 1000 (c) 1200
  15. 15.Best estimate of 60 × 97? (a) 600 (b) 60000 (c) 6000
  16. 16.Best estimate of 454 + 319? (a) 1000 (b) 800 (c) 600
  17. 17.Best estimate of 151 + 135? (a) 300 (b) 100 (c) 500
  18. 18.Best estimate of 621 + 767? (a) 1600 (b) 1400 (c) 1200
  19. 19.Best estimate of 56 × 42? (a) 24000 (b) 240 (c) 2400
  20. 20.Best estimate of 858 + 308? (a) 1400 (b) 1200 (c) 1000
  21. 21.Best estimate of 30 × 76? (a) 24000 (b) 240 (c) 2400
  22. 22.Best estimate of 654 + 253? (a) 1000 (b) 1200 (c) 800
  23. 23.Best estimate of 41 × 26? (a) 120 (b) 1200 (c) 12000
  24. 24.Best estimate of 79 × 46? (a) 4000 (b) 40000 (c) 400
  25. 25.Best estimate of 213 + 167? (a) 600 (b) 200 (c) 400
  26. 26.Best estimate of 38 × 47? (a) 2000 (b) 20000 (c) 200
  27. 27.Best estimate of 50 × 29? (a) 150 (b) 15000 (c) 1500
  28. 28.Best estimate of 521 + 208? (a) 500 (b) 700 (c) 900
  29. 29.Best estimate of 27 × 67? (a) 21000 (b) 2100 (c) 210
  30. 30.Best estimate of 438 + 358? (a) 1000 (b) 600 (c) 800
  31. 31.Best estimate of 520 + 392? (a) 700 (b) 1100 (c) 900
  32. 32.Best estimate of 856 + 284? (a) 1200 (b) 1400 (c) 1000
  33. 33.Best estimate of 94 × 51? (a) 4500 (b) 45000 (c) 450
  34. 34.Best estimate of 66 × 72? (a) 490 (b) 49000 (c) 4900
  35. 35.Best estimate of 63 × 66? (a) 420 (b) 4200 (c) 42000
  36. 36.Best estimate of 30 × 24? (a) 6000 (b) 600 (c) 60
  37. 37.Best estimate of 31 × 24? (a) 600 (b) 60 (c) 6000
  38. 38.Best estimate of 56 × 92? (a) 5400 (b) 54000 (c) 540
  39. 39.Best estimate of 456 + 564? (a) 900 (b) 1100 (c) 1300
  40. 40.Best estimate of 579 + 288? (a) 1100 (b) 700 (c) 900

Answer key

  1. 1000
  2. 1500
  3. 300
  4. 800
  5. 1800
  6. 2400
  7. 1600
  8. 3000
  9. 3500
  10. 1800
  11. 2700
  12. 800
  13. 1300
  14. 1200
  15. 6000
  16. 800
  17. 300
  18. 1400
  19. 2400
  20. 1200
  21. 2400
  22. 1000
  23. 1200
  24. 4000
  25. 400
  26. 2000
  27. 1500
  28. 700
  29. 2100
  30. 800
  31. 900
  32. 1200
  33. 4500
  34. 4900
  35. 4200
  36. 600
  37. 600
  38. 5400
  39. 1100
  40. 900

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