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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 796 · 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 28 × 16? (a) 600 (b) 60 (c) 6000
  2. 2.Best estimate of 504 + 776? (a) 1500 (b) 1300 (c) 1100
  3. 3.Best estimate of 36 × 66? (a) 280 (b) 2800 (c) 28000
  4. 4.Best estimate of 711 + 853? (a) 1600 (b) 1400 (c) 1800
  5. 5.Best estimate of 258 + 228? (a) 700 (b) 300 (c) 500
  6. 6.Best estimate of 702 + 498? (a) 1200 (b) 1400 (c) 1000
  7. 7.Best estimate of 66 × 24? (a) 140 (b) 14000 (c) 1400
  8. 8.Best estimate of 773 + 567? (a) 1600 (b) 1400 (c) 1200
  9. 9.Best estimate of 61 × 71? (a) 42000 (b) 4200 (c) 420
  10. 10.Best estimate of 336 + 122? (a) 200 (b) 600 (c) 400
  11. 11.Best estimate of 60 × 16? (a) 12000 (b) 1200 (c) 120
  12. 12.Best estimate of 565 + 516? (a) 1300 (b) 1100 (c) 900
  13. 13.Best estimate of 51 × 21? (a) 100 (b) 10000 (c) 1000
  14. 14.Best estimate of 52 × 61? (a) 30000 (b) 3000 (c) 300
  15. 15.Best estimate of 86 × 56? (a) 5400 (b) 540 (c) 54000
  16. 16.Best estimate of 484 + 133? (a) 800 (b) 400 (c) 600
  17. 17.Best estimate of 381 + 390? (a) 1000 (b) 800 (c) 600
  18. 18.Best estimate of 66 × 20? (a) 14000 (b) 140 (c) 1400
  19. 19.Best estimate of 621 + 137? (a) 700 (b) 500 (c) 900
  20. 20.Best estimate of 289 + 303? (a) 600 (b) 800 (c) 400
  21. 21.Best estimate of 761 + 438? (a) 1200 (b) 1400 (c) 1000
  22. 22.Best estimate of 555 + 593? (a) 1400 (b) 1000 (c) 1200
  23. 23.Best estimate of 331 + 130? (a) 400 (b) 600 (c) 200
  24. 24.Best estimate of 13 × 52? (a) 500 (b) 5000 (c) 50
  25. 25.Best estimate of 158 + 551? (a) 800 (b) 1000 (c) 600
  26. 26.Best estimate of 135 + 717? (a) 600 (b) 800 (c) 1000
  27. 27.Best estimate of 61 × 37? (a) 240 (b) 24000 (c) 2400
  28. 28.Best estimate of 685 + 607? (a) 1500 (b) 1300 (c) 1100
  29. 29.Best estimate of 86 × 16? (a) 1800 (b) 180 (c) 18000
  30. 30.Best estimate of 490 + 766? (a) 1300 (b) 1500 (c) 1100
  31. 31.Best estimate of 73 × 88? (a) 63000 (b) 630 (c) 6300
  32. 32.Best estimate of 96 × 36? (a) 400 (b) 4000 (c) 40000
  33. 33.Best estimate of 90 × 86? (a) 8100 (b) 810 (c) 81000
  34. 34.Best estimate of 93 × 16? (a) 1800 (b) 180 (c) 18000
  35. 35.Best estimate of 605 + 751? (a) 1600 (b) 1200 (c) 1400
  36. 36.Best estimate of 836 + 614? (a) 1600 (b) 1200 (c) 1400
  37. 37.Best estimate of 141 + 385? (a) 500 (b) 700 (c) 300
  38. 38.Best estimate of 14 × 82? (a) 800 (b) 8000 (c) 80
  39. 39.Best estimate of 96 × 93? (a) 90000 (b) 900 (c) 9000
  40. 40.Best estimate of 92 × 36? (a) 360 (b) 3600 (c) 36000

Answer key

  1. 600
  2. 1300
  3. 2800
  4. 1600
  5. 500
  6. 1200
  7. 1400
  8. 1400
  9. 4200
  10. 400
  11. 1200
  12. 1100
  13. 1000
  14. 3000
  15. 5400
  16. 600
  17. 800
  18. 1400
  19. 700
  20. 600
  21. 1200
  22. 1200
  23. 400
  24. 500
  25. 800
  26. 800
  27. 2400
  28. 1300
  29. 1800
  30. 1300
  31. 6300
  32. 4000
  33. 8100
  34. 1800
  35. 1400
  36. 1400
  37. 500
  38. 800
  39. 9000
  40. 3600

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