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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 356 · 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 24 × 46? (a) 1000 (b) 100 (c) 10000
  2. 2.Best estimate of 73 × 66? (a) 4900 (b) 490 (c) 49000
  3. 3.Best estimate of 77 × 49? (a) 40000 (b) 4000 (c) 400
  4. 4.Best estimate of 157 + 432? (a) 800 (b) 600 (c) 400
  5. 5.Best estimate of 82 × 96? (a) 80000 (b) 8000 (c) 800
  6. 6.Best estimate of 80 × 16? (a) 16000 (b) 1600 (c) 160
  7. 7.Best estimate of 97 × 33? (a) 3000 (b) 30000 (c) 300
  8. 8.Best estimate of 26 × 50? (a) 15000 (b) 1500 (c) 150
  9. 9.Best estimate of 91 × 42? (a) 360 (b) 36000 (c) 3600
  10. 10.Best estimate of 88 × 96? (a) 9000 (b) 90000 (c) 900
  11. 11.Best estimate of 864 + 754? (a) 1700 (b) 1500 (c) 1900
  12. 12.Best estimate of 402 + 523? (a) 1100 (b) 900 (c) 700
  13. 13.Best estimate of 262 + 716? (a) 800 (b) 1000 (c) 1200
  14. 14.Best estimate of 239 + 867? (a) 900 (b) 1100 (c) 1300
  15. 15.Best estimate of 186 + 664? (a) 900 (b) 700 (c) 1100
  16. 16.Best estimate of 70 × 56? (a) 4200 (b) 42000 (c) 420
  17. 17.Best estimate of 86 × 69? (a) 63000 (b) 630 (c) 6300
  18. 18.Best estimate of 240 + 392? (a) 400 (b) 600 (c) 800
  19. 19.Best estimate of 725 + 571? (a) 1300 (b) 1100 (c) 1500
  20. 20.Best estimate of 137 + 469? (a) 600 (b) 800 (c) 400
  21. 21.Best estimate of 96 × 96? (a) 1000 (b) 100000 (c) 10000
  22. 22.Best estimate of 66 × 51? (a) 3500 (b) 35000 (c) 350
  23. 23.Best estimate of 16 × 36? (a) 800 (b) 8000 (c) 80
  24. 24.Best estimate of 452 + 583? (a) 1300 (b) 900 (c) 1100
  25. 25.Best estimate of 792 + 298? (a) 1300 (b) 1100 (c) 900
  26. 26.Best estimate of 313 + 294? (a) 800 (b) 600 (c) 400
  27. 27.Best estimate of 88 × 86? (a) 8100 (b) 810 (c) 81000
  28. 28.Best estimate of 47 × 53? (a) 250 (b) 2500 (c) 25000
  29. 29.Best estimate of 17 × 62? (a) 12000 (b) 1200 (c) 120
  30. 30.Best estimate of 23 × 94? (a) 180 (b) 1800 (c) 18000
  31. 31.Best estimate of 272 + 796? (a) 1300 (b) 1100 (c) 900
  32. 32.Best estimate of 181 + 800? (a) 800 (b) 1000 (c) 1200
  33. 33.Best estimate of 440 + 784? (a) 1000 (b) 1200 (c) 1400
  34. 34.Best estimate of 17 × 66? (a) 1400 (b) 140 (c) 14000
  35. 35.Best estimate of 801 + 125? (a) 700 (b) 1100 (c) 900
  36. 36.Best estimate of 96 × 34? (a) 300 (b) 3000 (c) 30000
  37. 37.Best estimate of 762 + 373? (a) 1400 (b) 1000 (c) 1200
  38. 38.Best estimate of 66 × 68? (a) 4900 (b) 49000 (c) 490
  39. 39.Best estimate of 758 + 401? (a) 1400 (b) 1000 (c) 1200
  40. 40.Best estimate of 204 + 387? (a) 600 (b) 400 (c) 800

Answer key

  1. 1000
  2. 4900
  3. 4000
  4. 600
  5. 8000
  6. 1600
  7. 3000
  8. 1500
  9. 3600
  10. 9000
  11. 1700
  12. 900
  13. 1000
  14. 1100
  15. 900
  16. 4200
  17. 6300
  18. 600
  19. 1300
  20. 600
  21. 10000
  22. 3500
  23. 800
  24. 1100
  25. 1100
  26. 600
  27. 8100
  28. 2500
  29. 1200
  30. 1800
  31. 1100
  32. 1000
  33. 1200
  34. 1400
  35. 900
  36. 3000
  37. 1200
  38. 4900
  39. 1200
  40. 600

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