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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 952 · 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 741 + 291? (a) 1200 (b) 800 (c) 1000
  2. 2.Best estimate of 634 + 244? (a) 1000 (b) 600 (c) 800
  3. 3.Best estimate of 374 + 418? (a) 800 (b) 600 (c) 1000
  4. 4.Best estimate of 47 × 60? (a) 3000 (b) 300 (c) 30000
  5. 5.Best estimate of 68 × 30? (a) 2100 (b) 210 (c) 21000
  6. 6.Best estimate of 72 × 90? (a) 6300 (b) 63000 (c) 630
  7. 7.Best estimate of 662 + 612? (a) 1500 (b) 1100 (c) 1300
  8. 8.Best estimate of 323 + 489? (a) 600 (b) 1000 (c) 800
  9. 9.Best estimate of 747 + 477? (a) 1200 (b) 1400 (c) 1000
  10. 10.Best estimate of 143 + 165? (a) 300 (b) 100 (c) 500
  11. 11.Best estimate of 68 × 56? (a) 42000 (b) 420 (c) 4200
  12. 12.Best estimate of 747 + 451? (a) 1200 (b) 1400 (c) 1000
  13. 13.Best estimate of 565 + 481? (a) 900 (b) 1300 (c) 1100
  14. 14.Best estimate of 440 + 414? (a) 1000 (b) 600 (c) 800
  15. 15.Best estimate of 687 + 619? (a) 1300 (b) 1100 (c) 1500
  16. 16.Best estimate of 33 × 46? (a) 150 (b) 15000 (c) 1500
  17. 17.Best estimate of 51 × 49? (a) 250 (b) 25000 (c) 2500
  18. 18.Best estimate of 301 + 152? (a) 300 (b) 500 (c) 700
  19. 19.Best estimate of 341 + 392? (a) 500 (b) 900 (c) 700
  20. 20.Best estimate of 232 + 475? (a) 700 (b) 500 (c) 900
  21. 21.Best estimate of 392 + 406? (a) 600 (b) 1000 (c) 800
  22. 22.Best estimate of 16 × 54? (a) 1000 (b) 10000 (c) 100
  23. 23.Best estimate of 863 + 191? (a) 1300 (b) 1100 (c) 900
  24. 24.Best estimate of 147 + 453? (a) 600 (b) 400 (c) 800
  25. 25.Best estimate of 94 × 26? (a) 27000 (b) 2700 (c) 270
  26. 26.Best estimate of 76 × 29? (a) 24000 (b) 2400 (c) 240
  27. 27.Best estimate of 636 + 753? (a) 1200 (b) 1400 (c) 1600
  28. 28.Best estimate of 32 × 78? (a) 240 (b) 2400 (c) 24000
  29. 29.Best estimate of 717 + 322? (a) 800 (b) 1000 (c) 1200
  30. 30.Best estimate of 61 × 86? (a) 540 (b) 5400 (c) 54000
  31. 31.Best estimate of 144 + 279? (a) 200 (b) 600 (c) 400
  32. 32.Best estimate of 32 × 29? (a) 900 (b) 9000 (c) 90
  33. 33.Best estimate of 47 × 30? (a) 1500 (b) 150 (c) 15000
  34. 34.Best estimate of 340 + 514? (a) 600 (b) 800 (c) 1000
  35. 35.Best estimate of 248 + 667? (a) 900 (b) 1100 (c) 700
  36. 36.Best estimate of 875 + 527? (a) 1400 (b) 1200 (c) 1600
  37. 37.Best estimate of 498 + 349? (a) 800 (b) 600 (c) 1000
  38. 38.Best estimate of 845 + 621? (a) 1400 (b) 1600 (c) 1200
  39. 39.Best estimate of 259 + 498? (a) 600 (b) 1000 (c) 800
  40. 40.Best estimate of 26 × 47? (a) 1500 (b) 150 (c) 15000

Answer key

  1. 1000
  2. 800
  3. 800
  4. 3000
  5. 2100
  6. 6300
  7. 1300
  8. 800
  9. 1200
  10. 300
  11. 4200
  12. 1200
  13. 1100
  14. 800
  15. 1300
  16. 1500
  17. 2500
  18. 500
  19. 700
  20. 700
  21. 800
  22. 1000
  23. 1100
  24. 600
  25. 2700
  26. 2400
  27. 1400
  28. 2400
  29. 1000
  30. 5400
  31. 400
  32. 900
  33. 1500
  34. 800
  35. 900
  36. 1400
  37. 800
  38. 1400
  39. 800
  40. 1500

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