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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 901 · 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 594 + 166? (a) 1000 (b) 600 (c) 800
  2. 2.Best estimate of 82 × 52? (a) 400 (b) 40000 (c) 4000
  3. 3.Best estimate of 471 + 270? (a) 1000 (b) 800 (c) 600
  4. 4.Best estimate of 789 + 710? (a) 1500 (b) 1300 (c) 1700
  5. 5.Best estimate of 132 + 328? (a) 400 (b) 600 (c) 200
  6. 6.Best estimate of 815 + 876? (a) 1700 (b) 1900 (c) 1500
  7. 7.Best estimate of 678 + 692? (a) 1400 (b) 1200 (c) 1600
  8. 8.Best estimate of 721 + 429? (a) 1100 (b) 1300 (c) 900
  9. 9.Best estimate of 371 + 830? (a) 1400 (b) 1200 (c) 1000
  10. 10.Best estimate of 334 + 685? (a) 800 (b) 1200 (c) 1000
  11. 11.Best estimate of 539 + 672? (a) 1400 (b) 1000 (c) 1200
  12. 12.Best estimate of 553 + 200? (a) 1000 (b) 800 (c) 600
  13. 13.Best estimate of 537 + 620? (a) 1100 (b) 900 (c) 1300
  14. 14.Best estimate of 155 + 552? (a) 1000 (b) 800 (c) 600
  15. 15.Best estimate of 255 + 605? (a) 1100 (b) 900 (c) 700
  16. 16.Best estimate of 672 + 258? (a) 1000 (b) 800 (c) 1200
  17. 17.Best estimate of 178 + 270? (a) 700 (b) 500 (c) 300
  18. 18.Best estimate of 76 × 29? (a) 24000 (b) 2400 (c) 240
  19. 19.Best estimate of 169 + 234? (a) 400 (b) 200 (c) 600
  20. 20.Best estimate of 84 × 82? (a) 6400 (b) 64000 (c) 640
  21. 21.Best estimate of 20 × 26? (a) 6000 (b) 600 (c) 60
  22. 22.Best estimate of 60 × 18? (a) 1200 (b) 120 (c) 12000
  23. 23.Best estimate of 14 × 68? (a) 7000 (b) 70 (c) 700
  24. 24.Best estimate of 870 + 264? (a) 1400 (b) 1000 (c) 1200
  25. 25.Best estimate of 263 + 602? (a) 700 (b) 1100 (c) 900
  26. 26.Best estimate of 79 × 28? (a) 24000 (b) 240 (c) 2400
  27. 27.Best estimate of 168 + 331? (a) 500 (b) 300 (c) 700
  28. 28.Best estimate of 417 + 276? (a) 700 (b) 900 (c) 500
  29. 29.Best estimate of 684 + 244? (a) 1100 (b) 700 (c) 900
  30. 30.Best estimate of 124 + 815? (a) 1100 (b) 700 (c) 900
  31. 31.Best estimate of 74 × 26? (a) 21000 (b) 210 (c) 2100
  32. 32.Best estimate of 48 × 79? (a) 40000 (b) 4000 (c) 400
  33. 33.Best estimate of 137 + 563? (a) 900 (b) 700 (c) 500
  34. 34.Best estimate of 82 × 32? (a) 2400 (b) 24000 (c) 240
  35. 35.Best estimate of 262 + 853? (a) 1000 (b) 1200 (c) 1400
  36. 36.Best estimate of 790 + 513? (a) 1100 (b) 1300 (c) 1500
  37. 37.Best estimate of 484 + 222? (a) 700 (b) 500 (c) 900
  38. 38.Best estimate of 737 + 446? (a) 1100 (b) 900 (c) 1300
  39. 39.Best estimate of 83 × 94? (a) 7200 (b) 72000 (c) 720
  40. 40.Best estimate of 731 + 260? (a) 800 (b) 1000 (c) 1200

Answer key

  1. 800
  2. 4000
  3. 800
  4. 1500
  5. 400
  6. 1700
  7. 1400
  8. 1100
  9. 1200
  10. 1000
  11. 1200
  12. 800
  13. 1100
  14. 800
  15. 900
  16. 1000
  17. 500
  18. 2400
  19. 400
  20. 6400
  21. 600
  22. 1200
  23. 700
  24. 1200
  25. 900
  26. 2400
  27. 500
  28. 700
  29. 900
  30. 900
  31. 2100
  32. 4000
  33. 700
  34. 2400
  35. 1200
  36. 1300
  37. 700
  38. 1100
  39. 7200
  40. 1000

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