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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 224 · 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 72 × 87? (a) 6300 (b) 63000 (c) 630
  2. 2.Best estimate of 282 + 192? (a) 500 (b) 300 (c) 700
  3. 3.Best estimate of 641 + 642? (a) 1000 (b) 1400 (c) 1200
  4. 4.Best estimate of 96 × 60? (a) 6000 (b) 60000 (c) 600
  5. 5.Best estimate of 245 + 722? (a) 1100 (b) 900 (c) 700
  6. 6.Best estimate of 86 × 78? (a) 7200 (b) 72000 (c) 720
  7. 7.Best estimate of 868 + 185? (a) 900 (b) 1300 (c) 1100
  8. 8.Best estimate of 863 + 603? (a) 1700 (b) 1300 (c) 1500
  9. 9.Best estimate of 12 × 18? (a) 200 (b) 20 (c) 2000
  10. 10.Best estimate of 477 + 837? (a) 1300 (b) 1500 (c) 1100
  11. 11.Best estimate of 182 + 658? (a) 900 (b) 1100 (c) 700
  12. 12.Best estimate of 798 + 336? (a) 1300 (b) 900 (c) 1100
  13. 13.Best estimate of 72 × 82? (a) 56000 (b) 5600 (c) 560
  14. 14.Best estimate of 869 + 251? (a) 1200 (b) 1000 (c) 1400
  15. 15.Best estimate of 804 + 651? (a) 1500 (b) 1700 (c) 1300
  16. 16.Best estimate of 49 × 73? (a) 35000 (b) 350 (c) 3500
  17. 17.Best estimate of 137 + 400? (a) 700 (b) 500 (c) 300
  18. 18.Best estimate of 435 + 862? (a) 1300 (b) 1100 (c) 1500
  19. 19.Best estimate of 274 + 555? (a) 900 (b) 700 (c) 1100
  20. 20.Best estimate of 156 + 261? (a) 500 (b) 700 (c) 300
  21. 21.Best estimate of 87 × 83? (a) 72000 (b) 7200 (c) 720
  22. 22.Best estimate of 18 × 23? (a) 40 (b) 4000 (c) 400
  23. 23.Best estimate of 76 × 88? (a) 7200 (b) 72000 (c) 720
  24. 24.Best estimate of 878 + 462? (a) 1200 (b) 1400 (c) 1600
  25. 25.Best estimate of 18 × 83? (a) 1600 (b) 160 (c) 16000
  26. 26.Best estimate of 745 + 155? (a) 900 (b) 1100 (c) 700
  27. 27.Best estimate of 16 × 56? (a) 1200 (b) 12000 (c) 120
  28. 28.Best estimate of 313 + 587? (a) 700 (b) 900 (c) 1100
  29. 29.Best estimate of 14 × 80? (a) 800 (b) 8000 (c) 80
  30. 30.Best estimate of 319 + 775? (a) 1300 (b) 1100 (c) 900
  31. 31.Best estimate of 517 + 308? (a) 600 (b) 1000 (c) 800
  32. 32.Best estimate of 54 × 56? (a) 300 (b) 30000 (c) 3000
  33. 33.Best estimate of 81 × 48? (a) 400 (b) 4000 (c) 40000
  34. 34.Best estimate of 328 + 697? (a) 1200 (b) 800 (c) 1000
  35. 35.Best estimate of 401 + 355? (a) 800 (b) 1000 (c) 600
  36. 36.Best estimate of 74 × 48? (a) 350 (b) 35000 (c) 3500
  37. 37.Best estimate of 510 + 851? (a) 1400 (b) 1600 (c) 1200
  38. 38.Best estimate of 57 × 51? (a) 3000 (b) 300 (c) 30000
  39. 39.Best estimate of 717 + 312? (a) 1000 (b) 1200 (c) 800
  40. 40.Best estimate of 38 × 22? (a) 80 (b) 800 (c) 8000

Answer key

  1. 6300
  2. 500
  3. 1200
  4. 6000
  5. 900
  6. 7200
  7. 1100
  8. 1500
  9. 200
  10. 1300
  11. 900
  12. 1100
  13. 5600
  14. 1200
  15. 1500
  16. 3500
  17. 500
  18. 1300
  19. 900
  20. 500
  21. 7200
  22. 400
  23. 7200
  24. 1400
  25. 1600
  26. 900
  27. 1200
  28. 900
  29. 800
  30. 1100
  31. 800
  32. 3000
  33. 4000
  34. 1000
  35. 800
  36. 3500
  37. 1400
  38. 3000
  39. 1000
  40. 800

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