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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 941 · 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 870 + 506? (a) 1200 (b) 1400 (c) 1600
  2. 2.Best estimate of 18 × 54? (a) 10000 (b) 100 (c) 1000
  3. 3.Best estimate of 745 + 854? (a) 1800 (b) 1400 (c) 1600
  4. 4.Best estimate of 617 + 494? (a) 1100 (b) 900 (c) 1300
  5. 5.Best estimate of 840 + 546? (a) 1500 (b) 1300 (c) 1100
  6. 6.Best estimate of 438 + 335? (a) 700 (b) 900 (c) 500
  7. 7.Best estimate of 197 + 380? (a) 400 (b) 600 (c) 800
  8. 8.Best estimate of 360 + 176? (a) 800 (b) 400 (c) 600
  9. 9.Best estimate of 619 + 625? (a) 1000 (b) 1400 (c) 1200
  10. 10.Best estimate of 709 + 122? (a) 800 (b) 1000 (c) 600
  11. 11.Best estimate of 458 + 181? (a) 700 (b) 500 (c) 900
  12. 12.Best estimate of 94 × 66? (a) 63000 (b) 6300 (c) 630
  13. 13.Best estimate of 496 + 363? (a) 900 (b) 1100 (c) 700
  14. 14.Best estimate of 32 × 24? (a) 60 (b) 6000 (c) 600
  15. 15.Best estimate of 20 × 67? (a) 1400 (b) 14000 (c) 140
  16. 16.Best estimate of 444 + 378? (a) 1000 (b) 600 (c) 800
  17. 17.Best estimate of 39 × 30? (a) 120 (b) 12000 (c) 1200
  18. 18.Best estimate of 802 + 181? (a) 1200 (b) 800 (c) 1000
  19. 19.Best estimate of 79 × 79? (a) 640 (b) 6400 (c) 64000
  20. 20.Best estimate of 252 + 518? (a) 800 (b) 1000 (c) 600
  21. 21.Best estimate of 64 × 59? (a) 360 (b) 3600 (c) 36000
  22. 22.Best estimate of 839 + 487? (a) 1500 (b) 1300 (c) 1100
  23. 23.Best estimate of 576 + 137? (a) 900 (b) 700 (c) 500
  24. 24.Best estimate of 448 + 369? (a) 800 (b) 1000 (c) 600
  25. 25.Best estimate of 93 × 83? (a) 720 (b) 7200 (c) 72000
  26. 26.Best estimate of 354 + 174? (a) 600 (b) 800 (c) 400
  27. 27.Best estimate of 41 × 53? (a) 200 (b) 2000 (c) 20000
  28. 28.Best estimate of 59 × 32? (a) 1800 (b) 18000 (c) 180
  29. 29.Best estimate of 84 × 74? (a) 5600 (b) 56000 (c) 560
  30. 30.Best estimate of 330 + 537? (a) 600 (b) 800 (c) 1000
  31. 31.Best estimate of 13 × 42? (a) 400 (b) 4000 (c) 40
  32. 32.Best estimate of 88 × 36? (a) 36000 (b) 3600 (c) 360
  33. 33.Best estimate of 56 × 94? (a) 540 (b) 54000 (c) 5400
  34. 34.Best estimate of 846 + 247? (a) 1200 (b) 1000 (c) 800
  35. 35.Best estimate of 83 × 68? (a) 5600 (b) 56000 (c) 560
  36. 36.Best estimate of 38 × 29? (a) 1200 (b) 12000 (c) 120
  37. 37.Best estimate of 20 × 36? (a) 80 (b) 8000 (c) 800
  38. 38.Best estimate of 26 × 80? (a) 240 (b) 24000 (c) 2400
  39. 39.Best estimate of 14 × 83? (a) 8000 (b) 80 (c) 800
  40. 40.Best estimate of 290 + 234? (a) 700 (b) 300 (c) 500

Answer key

  1. 1400
  2. 1000
  3. 1600
  4. 1100
  5. 1300
  6. 700
  7. 600
  8. 600
  9. 1200
  10. 800
  11. 700
  12. 6300
  13. 900
  14. 600
  15. 1400
  16. 800
  17. 1200
  18. 1000
  19. 6400
  20. 800
  21. 3600
  22. 1300
  23. 700
  24. 800
  25. 7200
  26. 600
  27. 2000
  28. 1800
  29. 5600
  30. 800
  31. 400
  32. 3600
  33. 5400
  34. 1000
  35. 5600
  36. 1200
  37. 800
  38. 2400
  39. 800
  40. 500

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