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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 373 · 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 56 × 31? (a) 1800 (b) 18000 (c) 180
  2. 2.Best estimate of 800 + 727? (a) 1500 (b) 1300 (c) 1700
  3. 3.Best estimate of 74 × 36? (a) 28000 (b) 280 (c) 2800
  4. 4.Best estimate of 281 + 458? (a) 1000 (b) 600 (c) 800
  5. 5.Best estimate of 17 × 54? (a) 1000 (b) 100 (c) 10000
  6. 6.Best estimate of 229 + 205? (a) 400 (b) 200 (c) 600
  7. 7.Best estimate of 687 + 355? (a) 1300 (b) 1100 (c) 900
  8. 8.Best estimate of 773 + 164? (a) 1000 (b) 800 (c) 1200
  9. 9.Best estimate of 33 × 28? (a) 90 (b) 900 (c) 9000
  10. 10.Best estimate of 66 × 27? (a) 2100 (b) 210 (c) 21000
  11. 11.Best estimate of 78 × 40? (a) 320 (b) 32000 (c) 3200
  12. 12.Best estimate of 46 × 67? (a) 35000 (b) 3500 (c) 350
  13. 13.Best estimate of 18 × 26? (a) 600 (b) 6000 (c) 60
  14. 14.Best estimate of 539 + 376? (a) 1100 (b) 700 (c) 900
  15. 15.Best estimate of 71 × 21? (a) 14000 (b) 140 (c) 1400
  16. 16.Best estimate of 19 × 54? (a) 10000 (b) 1000 (c) 100
  17. 17.Best estimate of 27 × 32? (a) 9000 (b) 90 (c) 900
  18. 18.Best estimate of 79 × 29? (a) 240 (b) 2400 (c) 24000
  19. 19.Best estimate of 78 × 63? (a) 4800 (b) 48000 (c) 480
  20. 20.Best estimate of 849 + 288? (a) 900 (b) 1100 (c) 1300
  21. 21.Best estimate of 430 + 716? (a) 1100 (b) 1300 (c) 900
  22. 22.Best estimate of 586 + 351? (a) 1000 (b) 1200 (c) 800
  23. 23.Best estimate of 31 × 83? (a) 240 (b) 24000 (c) 2400
  24. 24.Best estimate of 66 × 47? (a) 3500 (b) 350 (c) 35000
  25. 25.Best estimate of 327 + 590? (a) 700 (b) 1100 (c) 900
  26. 26.Best estimate of 13 × 91? (a) 900 (b) 9000 (c) 90
  27. 27.Best estimate of 763 + 165? (a) 800 (b) 1000 (c) 1200
  28. 28.Best estimate of 131 + 486? (a) 800 (b) 600 (c) 400
  29. 29.Best estimate of 204 + 678? (a) 900 (b) 1100 (c) 700
  30. 30.Best estimate of 60 × 41? (a) 2400 (b) 24000 (c) 240
  31. 31.Best estimate of 260 + 130? (a) 400 (b) 200 (c) 600
  32. 32.Best estimate of 362 + 598? (a) 1200 (b) 800 (c) 1000
  33. 33.Best estimate of 81 × 37? (a) 320 (b) 32000 (c) 3200
  34. 34.Best estimate of 93 × 20? (a) 180 (b) 1800 (c) 18000
  35. 35.Best estimate of 336 + 467? (a) 600 (b) 1000 (c) 800
  36. 36.Best estimate of 506 + 240? (a) 500 (b) 900 (c) 700
  37. 37.Best estimate of 27 × 52? (a) 150 (b) 15000 (c) 1500
  38. 38.Best estimate of 270 + 355? (a) 500 (b) 700 (c) 900
  39. 39.Best estimate of 183 + 347? (a) 300 (b) 500 (c) 700
  40. 40.Best estimate of 83 × 96? (a) 80000 (b) 8000 (c) 800

Answer key

  1. 1800
  2. 1500
  3. 2800
  4. 800
  5. 1000
  6. 400
  7. 1100
  8. 1000
  9. 900
  10. 2100
  11. 3200
  12. 3500
  13. 600
  14. 900
  15. 1400
  16. 1000
  17. 900
  18. 2400
  19. 4800
  20. 1100
  21. 1100
  22. 1000
  23. 2400
  24. 3500
  25. 900
  26. 900
  27. 1000
  28. 600
  29. 900
  30. 2400
  31. 400
  32. 1000
  33. 3200
  34. 1800
  35. 800
  36. 700
  37. 1500
  38. 700
  39. 500
  40. 8000

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