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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 696 · 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 816 + 722? (a) 1300 (b) 1700 (c) 1500
  2. 2.Best estimate of 438 + 811? (a) 1000 (b) 1400 (c) 1200
  3. 3.Best estimate of 582 + 264? (a) 700 (b) 1100 (c) 900
  4. 4.Best estimate of 783 + 375? (a) 1000 (b) 1200 (c) 1400
  5. 5.Best estimate of 396 + 651? (a) 900 (b) 1300 (c) 1100
  6. 6.Best estimate of 438 + 366? (a) 1000 (b) 600 (c) 800
  7. 7.Best estimate of 44 × 51? (a) 2000 (b) 20000 (c) 200
  8. 8.Best estimate of 132 + 245? (a) 500 (b) 100 (c) 300
  9. 9.Best estimate of 88 × 69? (a) 63000 (b) 6300 (c) 630
  10. 10.Best estimate of 540 + 747? (a) 1000 (b) 1400 (c) 1200
  11. 11.Best estimate of 633 + 309? (a) 700 (b) 1100 (c) 900
  12. 12.Best estimate of 173 + 480? (a) 500 (b) 700 (c) 900
  13. 13.Best estimate of 796 + 181? (a) 1200 (b) 800 (c) 1000
  14. 14.Best estimate of 191 + 287? (a) 700 (b) 500 (c) 300
  15. 15.Best estimate of 66 × 81? (a) 5600 (b) 56000 (c) 560
  16. 16.Best estimate of 231 + 373? (a) 600 (b) 800 (c) 400
  17. 17.Best estimate of 266 + 722? (a) 1000 (b) 800 (c) 1200
  18. 18.Best estimate of 18 × 16? (a) 40 (b) 400 (c) 4000
  19. 19.Best estimate of 863 + 831? (a) 1900 (b) 1700 (c) 1500
  20. 20.Best estimate of 93 × 66? (a) 630 (b) 6300 (c) 63000
  21. 21.Best estimate of 48 × 26? (a) 150 (b) 1500 (c) 15000
  22. 22.Best estimate of 64 × 96? (a) 6000 (b) 60000 (c) 600
  23. 23.Best estimate of 73 × 43? (a) 280 (b) 28000 (c) 2800
  24. 24.Best estimate of 64 × 66? (a) 42000 (b) 420 (c) 4200
  25. 25.Best estimate of 69 × 29? (a) 2100 (b) 210 (c) 21000
  26. 26.Best estimate of 640 + 362? (a) 1200 (b) 1000 (c) 800
  27. 27.Best estimate of 677 + 614? (a) 1500 (b) 1300 (c) 1100
  28. 28.Best estimate of 321 + 438? (a) 500 (b) 700 (c) 900
  29. 29.Best estimate of 802 + 378? (a) 1000 (b) 1200 (c) 1400
  30. 30.Best estimate of 616 + 190? (a) 800 (b) 1000 (c) 600
  31. 31.Best estimate of 26 × 77? (a) 24000 (b) 240 (c) 2400
  32. 32.Best estimate of 295 + 532? (a) 1000 (b) 600 (c) 800
  33. 33.Best estimate of 236 + 610? (a) 600 (b) 1000 (c) 800
  34. 34.Best estimate of 182 + 787? (a) 1200 (b) 1000 (c) 800
  35. 35.Best estimate of 97 × 24? (a) 20000 (b) 2000 (c) 200
  36. 36.Best estimate of 48 × 41? (a) 20000 (b) 200 (c) 2000
  37. 37.Best estimate of 628 + 672? (a) 1500 (b) 1300 (c) 1100
  38. 38.Best estimate of 74 × 44? (a) 28000 (b) 280 (c) 2800
  39. 39.Best estimate of 454 + 201? (a) 500 (b) 900 (c) 700
  40. 40.Best estimate of 27 × 61? (a) 1800 (b) 180 (c) 18000

Answer key

  1. 1500
  2. 1200
  3. 900
  4. 1200
  5. 1100
  6. 800
  7. 2000
  8. 300
  9. 6300
  10. 1200
  11. 900
  12. 700
  13. 1000
  14. 500
  15. 5600
  16. 600
  17. 1000
  18. 400
  19. 1700
  20. 6300
  21. 1500
  22. 6000
  23. 2800
  24. 4200
  25. 2100
  26. 1000
  27. 1300
  28. 700
  29. 1200
  30. 800
  31. 2400
  32. 800
  33. 800
  34. 1000
  35. 2000
  36. 2000
  37. 1300
  38. 2800
  39. 700
  40. 1800

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