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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 979 · 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 77 × 16? (a) 1600 (b) 16000 (c) 160
  2. 2.Best estimate of 33 × 84? (a) 240 (b) 2400 (c) 24000
  3. 3.Best estimate of 710 + 616? (a) 1500 (b) 1300 (c) 1100
  4. 4.Best estimate of 328 + 672? (a) 1200 (b) 1000 (c) 800
  5. 5.Best estimate of 717 + 649? (a) 1500 (b) 1100 (c) 1300
  6. 6.Best estimate of 72 × 43? (a) 2800 (b) 280 (c) 28000
  7. 7.Best estimate of 313 + 136? (a) 400 (b) 200 (c) 600
  8. 8.Best estimate of 535 + 560? (a) 900 (b) 1300 (c) 1100
  9. 9.Best estimate of 419 + 129? (a) 700 (b) 300 (c) 500
  10. 10.Best estimate of 264 + 143? (a) 400 (b) 200 (c) 600
  11. 11.Best estimate of 96 × 81? (a) 80000 (b) 8000 (c) 800
  12. 12.Best estimate of 865 + 704? (a) 1600 (b) 1800 (c) 1400
  13. 13.Best estimate of 642 + 435? (a) 1200 (b) 800 (c) 1000
  14. 14.Best estimate of 13 × 34? (a) 3000 (b) 30 (c) 300
  15. 15.Best estimate of 784 + 356? (a) 1400 (b) 1000 (c) 1200
  16. 16.Best estimate of 46 × 98? (a) 50000 (b) 5000 (c) 500
  17. 17.Best estimate of 866 + 264? (a) 1200 (b) 1400 (c) 1000
  18. 18.Best estimate of 233 + 289? (a) 700 (b) 300 (c) 500
  19. 19.Best estimate of 78 × 27? (a) 240 (b) 24000 (c) 2400
  20. 20.Best estimate of 13 × 61? (a) 600 (b) 60 (c) 6000
  21. 21.Best estimate of 188 + 121? (a) 500 (b) 100 (c) 300
  22. 22.Best estimate of 22 × 69? (a) 140 (b) 14000 (c) 1400
  23. 23.Best estimate of 23 × 12? (a) 200 (b) 20 (c) 2000
  24. 24.Best estimate of 68 × 27? (a) 21000 (b) 2100 (c) 210
  25. 25.Best estimate of 77 × 56? (a) 48000 (b) 4800 (c) 480
  26. 26.Best estimate of 82 × 54? (a) 40000 (b) 4000 (c) 400
  27. 27.Best estimate of 30 × 26? (a) 900 (b) 90 (c) 9000
  28. 28.Best estimate of 26 × 60? (a) 1800 (b) 180 (c) 18000
  29. 29.Best estimate of 227 + 240? (a) 600 (b) 400 (c) 200
  30. 30.Best estimate of 528 + 149? (a) 600 (b) 400 (c) 800
  31. 31.Best estimate of 175 + 217? (a) 600 (b) 400 (c) 200
  32. 32.Best estimate of 578 + 607? (a) 1200 (b) 1400 (c) 1000
  33. 33.Best estimate of 434 + 372? (a) 600 (b) 1000 (c) 800
  34. 34.Best estimate of 89 × 76? (a) 7200 (b) 72000 (c) 720
  35. 35.Best estimate of 475 + 465? (a) 800 (b) 1200 (c) 1000
  36. 36.Best estimate of 64 × 36? (a) 24000 (b) 2400 (c) 240
  37. 37.Best estimate of 31 × 32? (a) 9000 (b) 900 (c) 90
  38. 38.Best estimate of 80 × 51? (a) 40000 (b) 400 (c) 4000
  39. 39.Best estimate of 414 + 752? (a) 1200 (b) 1400 (c) 1000
  40. 40.Best estimate of 631 + 411? (a) 1200 (b) 1000 (c) 800

Answer key

  1. 1600
  2. 2400
  3. 1300
  4. 1000
  5. 1300
  6. 2800
  7. 400
  8. 1100
  9. 500
  10. 400
  11. 8000
  12. 1600
  13. 1000
  14. 300
  15. 1200
  16. 5000
  17. 1200
  18. 500
  19. 2400
  20. 600
  21. 300
  22. 1400
  23. 200
  24. 2100
  25. 4800
  26. 4000
  27. 900
  28. 1800
  29. 400
  30. 600
  31. 400
  32. 1200
  33. 800
  34. 7200
  35. 1000
  36. 2400
  37. 900
  38. 4000
  39. 1200
  40. 1000

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