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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 876 · 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 26 × 30? (a) 9000 (b) 900 (c) 90
  2. 2.Best estimate of 46 × 78? (a) 400 (b) 40000 (c) 4000
  3. 3.Best estimate of 31 × 88? (a) 2700 (b) 270 (c) 27000
  4. 4.Best estimate of 52 × 42? (a) 2000 (b) 20000 (c) 200
  5. 5.Best estimate of 742 + 765? (a) 1500 (b) 1300 (c) 1700
  6. 6.Best estimate of 43 × 12? (a) 4000 (b) 400 (c) 40
  7. 7.Best estimate of 94 × 31? (a) 2700 (b) 270 (c) 27000
  8. 8.Best estimate of 575 + 276? (a) 1100 (b) 900 (c) 700
  9. 9.Best estimate of 60 × 46? (a) 30000 (b) 300 (c) 3000
  10. 10.Best estimate of 288 + 479? (a) 1000 (b) 600 (c) 800
  11. 11.Best estimate of 853 + 202? (a) 900 (b) 1300 (c) 1100
  12. 12.Best estimate of 50 × 19? (a) 100 (b) 1000 (c) 10000
  13. 13.Best estimate of 670 + 632? (a) 1500 (b) 1100 (c) 1300
  14. 14.Best estimate of 571 + 704? (a) 1500 (b) 1100 (c) 1300
  15. 15.Best estimate of 673 + 634? (a) 1500 (b) 1300 (c) 1100
  16. 16.Best estimate of 818 + 822? (a) 1600 (b) 1800 (c) 1400
  17. 17.Best estimate of 319 + 511? (a) 600 (b) 1000 (c) 800
  18. 18.Best estimate of 49 × 50? (a) 250 (b) 25000 (c) 2500
  19. 19.Best estimate of 425 + 698? (a) 1300 (b) 1100 (c) 900
  20. 20.Best estimate of 57 × 50? (a) 3000 (b) 30000 (c) 300
  21. 21.Best estimate of 648 + 637? (a) 1200 (b) 1000 (c) 1400
  22. 22.Best estimate of 57 × 94? (a) 540 (b) 5400 (c) 54000
  23. 23.Best estimate of 23 × 67? (a) 1400 (b) 14000 (c) 140
  24. 24.Best estimate of 795 + 564? (a) 1200 (b) 1400 (c) 1600
  25. 25.Best estimate of 262 + 341? (a) 800 (b) 600 (c) 400
  26. 26.Best estimate of 724 + 129? (a) 1000 (b) 600 (c) 800
  27. 27.Best estimate of 81 × 60? (a) 480 (b) 48000 (c) 4800
  28. 28.Best estimate of 319 + 349? (a) 800 (b) 600 (c) 400
  29. 29.Best estimate of 719 + 833? (a) 1700 (b) 1300 (c) 1500
  30. 30.Best estimate of 79 × 21? (a) 1600 (b) 16000 (c) 160
  31. 31.Best estimate of 869 + 239? (a) 900 (b) 1100 (c) 1300
  32. 32.Best estimate of 93 × 43? (a) 36000 (b) 360 (c) 3600
  33. 33.Best estimate of 812 + 472? (a) 1500 (b) 1300 (c) 1100
  34. 34.Best estimate of 790 + 865? (a) 1700 (b) 1900 (c) 1500
  35. 35.Best estimate of 30 × 78? (a) 2400 (b) 24000 (c) 240
  36. 36.Best estimate of 36 × 39? (a) 160 (b) 16000 (c) 1600
  37. 37.Best estimate of 697 + 714? (a) 1200 (b) 1400 (c) 1600
  38. 38.Best estimate of 138 + 570? (a) 900 (b) 700 (c) 500
  39. 39.Best estimate of 505 + 208? (a) 500 (b) 900 (c) 700
  40. 40.Best estimate of 239 + 556? (a) 800 (b) 600 (c) 1000

Answer key

  1. 900
  2. 4000
  3. 2700
  4. 2000
  5. 1500
  6. 400
  7. 2700
  8. 900
  9. 3000
  10. 800
  11. 1100
  12. 1000
  13. 1300
  14. 1300
  15. 1300
  16. 1600
  17. 800
  18. 2500
  19. 1100
  20. 3000
  21. 1200
  22. 5400
  23. 1400
  24. 1400
  25. 600
  26. 800
  27. 4800
  28. 600
  29. 1500
  30. 1600
  31. 1100
  32. 3600
  33. 1300
  34. 1700
  35. 2400
  36. 1600
  37. 1400
  38. 700
  39. 700
  40. 800

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