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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 846 · 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 473 + 362? (a) 700 (b) 900 (c) 1100
  2. 2.Best estimate of 51 × 97? (a) 50000 (b) 5000 (c) 500
  3. 3.Best estimate of 741 + 519? (a) 1400 (b) 1200 (c) 1000
  4. 4.Best estimate of 291 + 841? (a) 1300 (b) 900 (c) 1100
  5. 5.Best estimate of 56 × 17? (a) 120 (b) 1200 (c) 12000
  6. 6.Best estimate of 23 × 52? (a) 10000 (b) 100 (c) 1000
  7. 7.Best estimate of 28 × 86? (a) 27000 (b) 270 (c) 2700
  8. 8.Best estimate of 795 + 861? (a) 1900 (b) 1700 (c) 1500
  9. 9.Best estimate of 39 × 21? (a) 8000 (b) 800 (c) 80
  10. 10.Best estimate of 627 + 456? (a) 1300 (b) 900 (c) 1100
  11. 11.Best estimate of 79 × 13? (a) 80 (b) 8000 (c) 800
  12. 12.Best estimate of 701 + 829? (a) 1700 (b) 1300 (c) 1500
  13. 13.Best estimate of 859 + 424? (a) 1300 (b) 1500 (c) 1100
  14. 14.Best estimate of 20 × 93? (a) 180 (b) 18000 (c) 1800
  15. 15.Best estimate of 34 × 56? (a) 18000 (b) 180 (c) 1800
  16. 16.Best estimate of 303 + 296? (a) 400 (b) 800 (c) 600
  17. 17.Best estimate of 251 + 724? (a) 1000 (b) 1200 (c) 800
  18. 18.Best estimate of 184 + 822? (a) 1000 (b) 1200 (c) 800
  19. 19.Best estimate of 789 + 183? (a) 1200 (b) 1000 (c) 800
  20. 20.Best estimate of 90 × 48? (a) 4500 (b) 45000 (c) 450
  21. 21.Best estimate of 86 × 89? (a) 810 (b) 8100 (c) 81000
  22. 22.Best estimate of 829 + 851? (a) 1500 (b) 1900 (c) 1700
  23. 23.Best estimate of 149 + 799? (a) 1100 (b) 700 (c) 900
  24. 24.Best estimate of 82 × 94? (a) 7200 (b) 72000 (c) 720
  25. 25.Best estimate of 78 × 26? (a) 2400 (b) 24000 (c) 240
  26. 26.Best estimate of 88 × 27? (a) 270 (b) 27000 (c) 2700
  27. 27.Best estimate of 500 + 288? (a) 600 (b) 1000 (c) 800
  28. 28.Best estimate of 243 + 638? (a) 800 (b) 1000 (c) 600
  29. 29.Best estimate of 59 × 36? (a) 240 (b) 24000 (c) 2400
  30. 30.Best estimate of 808 + 225? (a) 800 (b) 1200 (c) 1000
  31. 31.Best estimate of 719 + 761? (a) 1500 (b) 1300 (c) 1700
  32. 32.Best estimate of 630 + 278? (a) 900 (b) 700 (c) 1100
  33. 33.Best estimate of 701 + 143? (a) 600 (b) 800 (c) 1000
  34. 34.Best estimate of 53 × 18? (a) 1000 (b) 100 (c) 10000
  35. 35.Best estimate of 46 × 96? (a) 500 (b) 50000 (c) 5000
  36. 36.Best estimate of 264 + 719? (a) 1200 (b) 1000 (c) 800
  37. 37.Best estimate of 235 + 864? (a) 900 (b) 1300 (c) 1100
  38. 38.Best estimate of 26 × 79? (a) 240 (b) 2400 (c) 24000
  39. 39.Best estimate of 779 + 562? (a) 1600 (b) 1200 (c) 1400
  40. 40.Best estimate of 690 + 771? (a) 1300 (b) 1500 (c) 1700

Answer key

  1. 900
  2. 5000
  3. 1200
  4. 1100
  5. 1200
  6. 1000
  7. 2700
  8. 1700
  9. 800
  10. 1100
  11. 800
  12. 1500
  13. 1300
  14. 1800
  15. 1800
  16. 600
  17. 1000
  18. 1000
  19. 1000
  20. 4500
  21. 8100
  22. 1700
  23. 900
  24. 7200
  25. 2400
  26. 2700
  27. 800
  28. 800
  29. 2400
  30. 1000
  31. 1500
  32. 900
  33. 800
  34. 1000
  35. 5000
  36. 1000
  37. 1100
  38. 2400
  39. 1400
  40. 1500

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