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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 40 · 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 68 × 96? (a) 7000 (b) 70000 (c) 700
  2. 2.Best estimate of 533 + 504? (a) 1000 (b) 1200 (c) 800
  3. 3.Best estimate of 97 × 59? (a) 600 (b) 60000 (c) 6000
  4. 4.Best estimate of 43 × 16? (a) 80 (b) 800 (c) 8000
  5. 5.Best estimate of 14 × 87? (a) 90 (b) 9000 (c) 900
  6. 6.Best estimate of 79 × 68? (a) 5600 (b) 560 (c) 56000
  7. 7.Best estimate of 222 + 729? (a) 900 (b) 1100 (c) 700
  8. 8.Best estimate of 26 × 91? (a) 2700 (b) 270 (c) 27000
  9. 9.Best estimate of 368 + 511? (a) 900 (b) 1100 (c) 700
  10. 10.Best estimate of 701 + 505? (a) 1200 (b) 1400 (c) 1000
  11. 11.Best estimate of 30 × 67? (a) 2100 (b) 21000 (c) 210
  12. 12.Best estimate of 29 × 76? (a) 240 (b) 24000 (c) 2400
  13. 13.Best estimate of 96 × 12? (a) 1000 (b) 100 (c) 10000
  14. 14.Best estimate of 302 + 284? (a) 400 (b) 600 (c) 800
  15. 15.Best estimate of 765 + 576? (a) 1400 (b) 1200 (c) 1600
  16. 16.Best estimate of 195 + 274? (a) 500 (b) 300 (c) 700
  17. 17.Best estimate of 66 × 97? (a) 7000 (b) 700 (c) 70000
  18. 18.Best estimate of 399 + 322? (a) 900 (b) 700 (c) 500
  19. 19.Best estimate of 20 × 69? (a) 1400 (b) 140 (c) 14000
  20. 20.Best estimate of 797 + 767? (a) 1800 (b) 1600 (c) 1400
  21. 21.Best estimate of 86 × 62? (a) 54000 (b) 540 (c) 5400
  22. 22.Best estimate of 621 + 534? (a) 1100 (b) 900 (c) 1300
  23. 23.Best estimate of 76 × 90? (a) 720 (b) 72000 (c) 7200
  24. 24.Best estimate of 263 + 190? (a) 500 (b) 300 (c) 700
  25. 25.Best estimate of 33 × 87? (a) 27000 (b) 2700 (c) 270
  26. 26.Best estimate of 33 × 83? (a) 2400 (b) 240 (c) 24000
  27. 27.Best estimate of 490 + 197? (a) 500 (b) 700 (c) 900
  28. 28.Best estimate of 510 + 441? (a) 900 (b) 1100 (c) 700
  29. 29.Best estimate of 403 + 584? (a) 1200 (b) 800 (c) 1000
  30. 30.Best estimate of 856 + 497? (a) 1200 (b) 1600 (c) 1400
  31. 31.Best estimate of 846 + 875? (a) 1700 (b) 1900 (c) 1500
  32. 32.Best estimate of 651 + 597? (a) 1300 (b) 1100 (c) 1500
  33. 33.Best estimate of 202 + 349? (a) 300 (b) 500 (c) 700
  34. 34.Best estimate of 60 × 16? (a) 1200 (b) 12000 (c) 120
  35. 35.Best estimate of 813 + 275? (a) 1100 (b) 1300 (c) 900
  36. 36.Best estimate of 64 × 96? (a) 6000 (b) 60000 (c) 600
  37. 37.Best estimate of 358 + 556? (a) 1200 (b) 1000 (c) 800
  38. 38.Best estimate of 36 × 87? (a) 3600 (b) 36000 (c) 360
  39. 39.Best estimate of 522 + 510? (a) 1200 (b) 1000 (c) 800
  40. 40.Best estimate of 877 + 741? (a) 1600 (b) 1800 (c) 1400

Answer key

  1. 7000
  2. 1000
  3. 6000
  4. 800
  5. 900
  6. 5600
  7. 900
  8. 2700
  9. 900
  10. 1200
  11. 2100
  12. 2400
  13. 1000
  14. 600
  15. 1400
  16. 500
  17. 7000
  18. 700
  19. 1400
  20. 1600
  21. 5400
  22. 1100
  23. 7200
  24. 500
  25. 2700
  26. 2400
  27. 700
  28. 900
  29. 1000
  30. 1400
  31. 1700
  32. 1300
  33. 500
  34. 1200
  35. 1100
  36. 6000
  37. 1000
  38. 3600
  39. 1000
  40. 1600

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