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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 410 · 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 14 × 20? (a) 20 (b) 200 (c) 2000
  2. 2.Best estimate of 475 + 135? (a) 800 (b) 600 (c) 400
  3. 3.Best estimate of 12 × 23? (a) 20 (b) 200 (c) 2000
  4. 4.Best estimate of 53 × 19? (a) 10000 (b) 1000 (c) 100
  5. 5.Best estimate of 13 × 68? (a) 7000 (b) 70 (c) 700
  6. 6.Best estimate of 501 + 708? (a) 1200 (b) 1000 (c) 1400
  7. 7.Best estimate of 98 × 12? (a) 10000 (b) 100 (c) 1000
  8. 8.Best estimate of 666 + 299? (a) 1200 (b) 1000 (c) 800
  9. 9.Best estimate of 29 × 97? (a) 30000 (b) 300 (c) 3000
  10. 10.Best estimate of 404 + 405? (a) 1000 (b) 600 (c) 800
  11. 11.Best estimate of 193 + 829? (a) 1000 (b) 1200 (c) 800
  12. 12.Best estimate of 741 + 670? (a) 1200 (b) 1600 (c) 1400
  13. 13.Best estimate of 292 + 456? (a) 800 (b) 600 (c) 1000
  14. 14.Best estimate of 23 × 88? (a) 180 (b) 1800 (c) 18000
  15. 15.Best estimate of 80 × 88? (a) 720 (b) 7200 (c) 72000
  16. 16.Best estimate of 94 × 39? (a) 3600 (b) 36000 (c) 360
  17. 17.Best estimate of 209 + 556? (a) 800 (b) 1000 (c) 600
  18. 18.Best estimate of 56 × 18? (a) 1200 (b) 12000 (c) 120
  19. 19.Best estimate of 79 × 30? (a) 24000 (b) 2400 (c) 240
  20. 20.Best estimate of 16 × 36? (a) 80 (b) 8000 (c) 800
  21. 21.Best estimate of 36 × 43? (a) 1600 (b) 16000 (c) 160
  22. 22.Best estimate of 39 × 51? (a) 20000 (b) 2000 (c) 200
  23. 23.Best estimate of 281 + 200? (a) 300 (b) 700 (c) 500
  24. 24.Best estimate of 96 × 98? (a) 1000 (b) 100000 (c) 10000
  25. 25.Best estimate of 519 + 694? (a) 1000 (b) 1200 (c) 1400
  26. 26.Best estimate of 37 × 87? (a) 3600 (b) 360 (c) 36000
  27. 27.Best estimate of 53 × 70? (a) 3500 (b) 350 (c) 35000
  28. 28.Best estimate of 308 + 442? (a) 500 (b) 900 (c) 700
  29. 29.Best estimate of 809 + 765? (a) 1800 (b) 1600 (c) 1400
  30. 30.Best estimate of 754 + 245? (a) 1200 (b) 1000 (c) 800
  31. 31.Best estimate of 23 × 12? (a) 20 (b) 200 (c) 2000
  32. 32.Best estimate of 528 + 738? (a) 1200 (b) 1400 (c) 1000
  33. 33.Best estimate of 29 × 79? (a) 240 (b) 2400 (c) 24000
  34. 34.Best estimate of 28 × 21? (a) 60 (b) 6000 (c) 600
  35. 35.Best estimate of 36 × 41? (a) 1600 (b) 16000 (c) 160
  36. 36.Best estimate of 66 × 62? (a) 420 (b) 42000 (c) 4200
  37. 37.Best estimate of 24 × 12? (a) 20 (b) 2000 (c) 200
  38. 38.Best estimate of 281 + 125? (a) 400 (b) 600 (c) 200
  39. 39.Best estimate of 43 × 76? (a) 3200 (b) 320 (c) 32000
  40. 40.Best estimate of 57 × 96? (a) 60000 (b) 600 (c) 6000

Answer key

  1. 200
  2. 600
  3. 200
  4. 1000
  5. 700
  6. 1200
  7. 1000
  8. 1000
  9. 3000
  10. 800
  11. 1000
  12. 1400
  13. 800
  14. 1800
  15. 7200
  16. 3600
  17. 800
  18. 1200
  19. 2400
  20. 800
  21. 1600
  22. 2000
  23. 500
  24. 10000
  25. 1200
  26. 3600
  27. 3500
  28. 700
  29. 1600
  30. 1000
  31. 200
  32. 1200
  33. 2400
  34. 600
  35. 1600
  36. 4200
  37. 200
  38. 400
  39. 3200
  40. 6000

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