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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 196 · 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 76 × 37? (a) 3200 (b) 32000 (c) 320
  2. 2.Best estimate of 44 × 84? (a) 320 (b) 32000 (c) 3200
  3. 3.Best estimate of 26 × 88? (a) 27000 (b) 270 (c) 2700
  4. 4.Best estimate of 91 × 20? (a) 180 (b) 18000 (c) 1800
  5. 5.Best estimate of 71 × 87? (a) 6300 (b) 63000 (c) 630
  6. 6.Best estimate of 76 × 32? (a) 240 (b) 24000 (c) 2400
  7. 7.Best estimate of 677 + 808? (a) 1500 (b) 1700 (c) 1300
  8. 8.Best estimate of 151 + 302? (a) 500 (b) 700 (c) 300
  9. 9.Best estimate of 98 × 27? (a) 3000 (b) 300 (c) 30000
  10. 10.Best estimate of 755 + 281? (a) 1100 (b) 900 (c) 1300
  11. 11.Best estimate of 353 + 629? (a) 800 (b) 1000 (c) 1200
  12. 12.Best estimate of 71 × 70? (a) 490 (b) 4900 (c) 49000
  13. 13.Best estimate of 26 × 63? (a) 1800 (b) 180 (c) 18000
  14. 14.Best estimate of 666 + 825? (a) 1700 (b) 1500 (c) 1300
  15. 15.Best estimate of 22 × 52? (a) 10000 (b) 100 (c) 1000
  16. 16.Best estimate of 132 + 545? (a) 800 (b) 600 (c) 400
  17. 17.Best estimate of 96 × 72? (a) 70000 (b) 700 (c) 7000
  18. 18.Best estimate of 332 + 695? (a) 1200 (b) 800 (c) 1000
  19. 19.Best estimate of 814 + 629? (a) 1200 (b) 1600 (c) 1400
  20. 20.Best estimate of 200 + 596? (a) 800 (b) 600 (c) 1000
  21. 21.Best estimate of 624 + 497? (a) 1100 (b) 900 (c) 1300
  22. 22.Best estimate of 137 + 151? (a) 100 (b) 500 (c) 300
  23. 23.Best estimate of 36 × 18? (a) 8000 (b) 800 (c) 80
  24. 24.Best estimate of 120 + 569? (a) 700 (b) 900 (c) 500
  25. 25.Best estimate of 88 × 18? (a) 180 (b) 18000 (c) 1800
  26. 26.Best estimate of 26 × 78? (a) 24000 (b) 240 (c) 2400
  27. 27.Best estimate of 50 × 40? (a) 20000 (b) 2000 (c) 200
  28. 28.Best estimate of 302 + 151? (a) 500 (b) 300 (c) 700
  29. 29.Best estimate of 453 + 301? (a) 800 (b) 1000 (c) 600
  30. 30.Best estimate of 51 × 36? (a) 2000 (b) 200 (c) 20000
  31. 31.Best estimate of 48 × 61? (a) 30000 (b) 3000 (c) 300
  32. 32.Best estimate of 527 + 716? (a) 1400 (b) 1200 (c) 1000
  33. 33.Best estimate of 605 + 542? (a) 1300 (b) 1100 (c) 900
  34. 34.Best estimate of 57 × 46? (a) 30000 (b) 3000 (c) 300
  35. 35.Best estimate of 542 + 324? (a) 800 (b) 600 (c) 1000
  36. 36.Best estimate of 56 × 34? (a) 18000 (b) 180 (c) 1800
  37. 37.Best estimate of 36 × 93? (a) 360 (b) 36000 (c) 3600
  38. 38.Best estimate of 70 × 38? (a) 280 (b) 2800 (c) 28000
  39. 39.Best estimate of 82 × 20? (a) 16000 (b) 160 (c) 1600
  40. 40.Best estimate of 46 × 21? (a) 100 (b) 1000 (c) 10000

Answer key

  1. 3200
  2. 3200
  3. 2700
  4. 1800
  5. 6300
  6. 2400
  7. 1500
  8. 500
  9. 3000
  10. 1100
  11. 1000
  12. 4900
  13. 1800
  14. 1500
  15. 1000
  16. 600
  17. 7000
  18. 1000
  19. 1400
  20. 800
  21. 1100
  22. 300
  23. 800
  24. 700
  25. 1800
  26. 2400
  27. 2000
  28. 500
  29. 800
  30. 2000
  31. 3000
  32. 1200
  33. 1100
  34. 3000
  35. 800
  36. 1800
  37. 3600
  38. 2800
  39. 1600
  40. 1000

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