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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 616 · 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 86 × 92? (a) 81000 (b) 810 (c) 8100
  2. 2.Best estimate of 241 + 693? (a) 700 (b) 900 (c) 1100
  3. 3.Best estimate of 26 × 91? (a) 2700 (b) 270 (c) 27000
  4. 4.Best estimate of 195 + 662? (a) 900 (b) 1100 (c) 700
  5. 5.Best estimate of 48 × 48? (a) 250 (b) 2500 (c) 25000
  6. 6.Best estimate of 213 + 573? (a) 1000 (b) 800 (c) 600
  7. 7.Best estimate of 96 × 64? (a) 6000 (b) 60000 (c) 600
  8. 8.Best estimate of 753 + 726? (a) 1500 (b) 1700 (c) 1300
  9. 9.Best estimate of 77 × 20? (a) 1600 (b) 16000 (c) 160
  10. 10.Best estimate of 66 × 64? (a) 420 (b) 42000 (c) 4200
  11. 11.Best estimate of 53 × 32? (a) 1500 (b) 15000 (c) 150
  12. 12.Best estimate of 60 × 17? (a) 12000 (b) 120 (c) 1200
  13. 13.Best estimate of 331 + 743? (a) 800 (b) 1000 (c) 1200
  14. 14.Best estimate of 70 × 59? (a) 420 (b) 4200 (c) 42000
  15. 15.Best estimate of 22 × 67? (a) 14000 (b) 1400 (c) 140
  16. 16.Best estimate of 66 × 43? (a) 28000 (b) 2800 (c) 280
  17. 17.Best estimate of 70 × 36? (a) 2800 (b) 280 (c) 28000
  18. 18.Best estimate of 532 + 276? (a) 800 (b) 600 (c) 1000
  19. 19.Best estimate of 695 + 766? (a) 1700 (b) 1500 (c) 1300
  20. 20.Best estimate of 34 × 29? (a) 900 (b) 90 (c) 9000
  21. 21.Best estimate of 93 × 24? (a) 1800 (b) 18000 (c) 180
  22. 22.Best estimate of 59 × 13? (a) 600 (b) 60 (c) 6000
  23. 23.Best estimate of 868 + 685? (a) 1800 (b) 1600 (c) 1400
  24. 24.Best estimate of 777 + 233? (a) 1000 (b) 1200 (c) 800
  25. 25.Best estimate of 18 × 71? (a) 14000 (b) 1400 (c) 140
  26. 26.Best estimate of 866 + 206? (a) 900 (b) 1300 (c) 1100
  27. 27.Best estimate of 792 + 863? (a) 1500 (b) 1700 (c) 1900
  28. 28.Best estimate of 733 + 281? (a) 800 (b) 1000 (c) 1200
  29. 29.Best estimate of 621 + 135? (a) 700 (b) 900 (c) 500
  30. 30.Best estimate of 360 + 571? (a) 1200 (b) 800 (c) 1000
  31. 31.Best estimate of 346 + 658? (a) 800 (b) 1200 (c) 1000
  32. 32.Best estimate of 49 × 20? (a) 1000 (b) 10000 (c) 100
  33. 33.Best estimate of 64 × 49? (a) 3000 (b) 30000 (c) 300
  34. 34.Best estimate of 741 + 613? (a) 1300 (b) 1100 (c) 1500
  35. 35.Best estimate of 39 × 93? (a) 3600 (b) 36000 (c) 360
  36. 36.Best estimate of 49 × 38? (a) 2000 (b) 200 (c) 20000
  37. 37.Best estimate of 831 + 149? (a) 700 (b) 1100 (c) 900
  38. 38.Best estimate of 16 × 17? (a) 400 (b) 40 (c) 4000
  39. 39.Best estimate of 54 × 66? (a) 35000 (b) 350 (c) 3500
  40. 40.Best estimate of 667 + 282? (a) 1000 (b) 1200 (c) 800

Answer key

  1. 8100
  2. 900
  3. 2700
  4. 900
  5. 2500
  6. 800
  7. 6000
  8. 1500
  9. 1600
  10. 4200
  11. 1500
  12. 1200
  13. 1000
  14. 4200
  15. 1400
  16. 2800
  17. 2800
  18. 800
  19. 1500
  20. 900
  21. 1800
  22. 600
  23. 1600
  24. 1000
  25. 1400
  26. 1100
  27. 1700
  28. 1000
  29. 700
  30. 1000
  31. 1000
  32. 1000
  33. 3000
  34. 1300
  35. 3600
  36. 2000
  37. 900
  38. 400
  39. 3500
  40. 1000

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