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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 511 · 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 59 × 53? (a) 300 (b) 3000 (c) 30000
  2. 2.Best estimate of 192 + 347? (a) 700 (b) 500 (c) 300
  3. 3.Best estimate of 88 × 38? (a) 3600 (b) 360 (c) 36000
  4. 4.Best estimate of 358 + 185? (a) 600 (b) 400 (c) 800
  5. 5.Best estimate of 213 + 394? (a) 600 (b) 800 (c) 400
  6. 6.Best estimate of 66 × 76? (a) 5600 (b) 560 (c) 56000
  7. 7.Best estimate of 395 + 859? (a) 1100 (b) 1500 (c) 1300
  8. 8.Best estimate of 94 × 17? (a) 1800 (b) 18000 (c) 180
  9. 9.Best estimate of 88 × 36? (a) 36000 (b) 3600 (c) 360
  10. 10.Best estimate of 618 + 735? (a) 1500 (b) 1100 (c) 1300
  11. 11.Best estimate of 312 + 133? (a) 400 (b) 200 (c) 600
  12. 12.Best estimate of 427 + 422? (a) 1000 (b) 600 (c) 800
  13. 13.Best estimate of 597 + 421? (a) 800 (b) 1200 (c) 1000
  14. 14.Best estimate of 44 × 30? (a) 12000 (b) 1200 (c) 120
  15. 15.Best estimate of 86 × 56? (a) 5400 (b) 54000 (c) 540
  16. 16.Best estimate of 232 + 518? (a) 700 (b) 900 (c) 500
  17. 17.Best estimate of 93 × 56? (a) 54000 (b) 540 (c) 5400
  18. 18.Best estimate of 324 + 149? (a) 400 (b) 200 (c) 600
  19. 19.Best estimate of 21 × 27? (a) 60 (b) 6000 (c) 600
  20. 20.Best estimate of 33 × 78? (a) 2400 (b) 24000 (c) 240
  21. 21.Best estimate of 36 × 68? (a) 280 (b) 2800 (c) 28000
  22. 22.Best estimate of 57 × 83? (a) 4800 (b) 480 (c) 48000
  23. 23.Best estimate of 595 + 436? (a) 1000 (b) 1200 (c) 800
  24. 24.Best estimate of 319 + 311? (a) 600 (b) 800 (c) 400
  25. 25.Best estimate of 94 × 71? (a) 63000 (b) 6300 (c) 630
  26. 26.Best estimate of 36 × 38? (a) 16000 (b) 1600 (c) 160
  27. 27.Best estimate of 314 + 481? (a) 800 (b) 1000 (c) 600
  28. 28.Best estimate of 61 × 90? (a) 5400 (b) 54000 (c) 540
  29. 29.Best estimate of 194 + 687? (a) 900 (b) 700 (c) 1100
  30. 30.Best estimate of 89 × 48? (a) 450 (b) 45000 (c) 4500
  31. 31.Best estimate of 39 × 92? (a) 36000 (b) 360 (c) 3600
  32. 32.Best estimate of 271 + 459? (a) 1000 (b) 600 (c) 800
  33. 33.Best estimate of 86 × 66? (a) 630 (b) 6300 (c) 63000
  34. 34.Best estimate of 864 + 279? (a) 1200 (b) 1400 (c) 1000
  35. 35.Best estimate of 259 + 420? (a) 700 (b) 900 (c) 500
  36. 36.Best estimate of 64 × 57? (a) 36000 (b) 360 (c) 3600
  37. 37.Best estimate of 41 × 96? (a) 4000 (b) 400 (c) 40000
  38. 38.Best estimate of 16 × 76? (a) 16000 (b) 1600 (c) 160
  39. 39.Best estimate of 21 × 16? (a) 400 (b) 40 (c) 4000
  40. 40.Best estimate of 705 + 269? (a) 1000 (b) 1200 (c) 800

Answer key

  1. 3000
  2. 500
  3. 3600
  4. 600
  5. 600
  6. 5600
  7. 1300
  8. 1800
  9. 3600
  10. 1300
  11. 400
  12. 800
  13. 1000
  14. 1200
  15. 5400
  16. 700
  17. 5400
  18. 400
  19. 600
  20. 2400
  21. 2800
  22. 4800
  23. 1000
  24. 600
  25. 6300
  26. 1600
  27. 800
  28. 5400
  29. 900
  30. 4500
  31. 3600
  32. 800
  33. 6300
  34. 1200
  35. 700
  36. 3600
  37. 4000
  38. 1600
  39. 400
  40. 1000

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