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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 898 · 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 94 × 27? (a) 27000 (b) 2700 (c) 270
  2. 2.Best estimate of 69 × 12? (a) 700 (b) 7000 (c) 70
  3. 3.Best estimate of 434 + 280? (a) 500 (b) 700 (c) 900
  4. 4.Best estimate of 47 × 13? (a) 50 (b) 5000 (c) 500
  5. 5.Best estimate of 646 + 505? (a) 1300 (b) 1100 (c) 900
  6. 6.Best estimate of 606 + 151? (a) 1000 (b) 600 (c) 800
  7. 7.Best estimate of 37 × 20? (a) 800 (b) 80 (c) 8000
  8. 8.Best estimate of 565 + 406? (a) 1000 (b) 1200 (c) 800
  9. 9.Best estimate of 760 + 649? (a) 1200 (b) 1400 (c) 1600
  10. 10.Best estimate of 187 + 369? (a) 600 (b) 400 (c) 800
  11. 11.Best estimate of 647 + 166? (a) 600 (b) 1000 (c) 800
  12. 12.Best estimate of 433 + 561? (a) 1200 (b) 1000 (c) 800
  13. 13.Best estimate of 31 × 80? (a) 240 (b) 2400 (c) 24000
  14. 14.Best estimate of 58 × 71? (a) 420 (b) 42000 (c) 4200
  15. 15.Best estimate of 564 + 267? (a) 900 (b) 1100 (c) 700
  16. 16.Best estimate of 320 + 385? (a) 500 (b) 700 (c) 900
  17. 17.Best estimate of 691 + 533? (a) 1400 (b) 1000 (c) 1200
  18. 18.Best estimate of 373 + 405? (a) 1000 (b) 600 (c) 800
  19. 19.Best estimate of 97 × 66? (a) 700 (b) 7000 (c) 70000
  20. 20.Best estimate of 242 + 705? (a) 1100 (b) 900 (c) 700
  21. 21.Best estimate of 690 + 606? (a) 1300 (b) 1500 (c) 1100
  22. 22.Best estimate of 33 × 62? (a) 18000 (b) 1800 (c) 180
  23. 23.Best estimate of 77 × 68? (a) 5600 (b) 56000 (c) 560
  24. 24.Best estimate of 67 × 24? (a) 1400 (b) 140 (c) 14000
  25. 25.Best estimate of 70 × 92? (a) 6300 (b) 63000 (c) 630
  26. 26.Best estimate of 28 × 86? (a) 270 (b) 2700 (c) 27000
  27. 27.Best estimate of 418 + 433? (a) 800 (b) 1000 (c) 600
  28. 28.Best estimate of 87 × 29? (a) 270 (b) 2700 (c) 27000
  29. 29.Best estimate of 329 + 285? (a) 800 (b) 400 (c) 600
  30. 30.Best estimate of 560 + 828? (a) 1600 (b) 1400 (c) 1200
  31. 31.Best estimate of 757 + 678? (a) 1300 (b) 1700 (c) 1500
  32. 32.Best estimate of 875 + 461? (a) 1400 (b) 1600 (c) 1200
  33. 33.Best estimate of 41 × 51? (a) 2000 (b) 200 (c) 20000
  34. 34.Best estimate of 793 + 754? (a) 1400 (b) 1600 (c) 1800
  35. 35.Best estimate of 796 + 853? (a) 1700 (b) 1900 (c) 1500
  36. 36.Best estimate of 16 × 49? (a) 10000 (b) 1000 (c) 100
  37. 37.Best estimate of 90 × 69? (a) 63000 (b) 630 (c) 6300
  38. 38.Best estimate of 33 × 84? (a) 240 (b) 24000 (c) 2400
  39. 39.Best estimate of 137 + 306? (a) 200 (b) 400 (c) 600
  40. 40.Best estimate of 171 + 296? (a) 300 (b) 500 (c) 700

Answer key

  1. 2700
  2. 700
  3. 700
  4. 500
  5. 1100
  6. 800
  7. 800
  8. 1000
  9. 1400
  10. 600
  11. 800
  12. 1000
  13. 2400
  14. 4200
  15. 900
  16. 700
  17. 1200
  18. 800
  19. 7000
  20. 900
  21. 1300
  22. 1800
  23. 5600
  24. 1400
  25. 6300
  26. 2700
  27. 800
  28. 2700
  29. 600
  30. 1400
  31. 1500
  32. 1400
  33. 2000
  34. 1600
  35. 1700
  36. 1000
  37. 6300
  38. 2400
  39. 400
  40. 500

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