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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 919 · 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 13 × 97? (a) 1000 (b) 10000 (c) 100
  2. 2.Best estimate of 73 × 79? (a) 56000 (b) 560 (c) 5600
  3. 3.Best estimate of 290 + 703? (a) 800 (b) 1000 (c) 1200
  4. 4.Best estimate of 20 × 41? (a) 8000 (b) 800 (c) 80
  5. 5.Best estimate of 87 × 94? (a) 810 (b) 81000 (c) 8100
  6. 6.Best estimate of 92 × 60? (a) 5400 (b) 54000 (c) 540
  7. 7.Best estimate of 57 × 83? (a) 4800 (b) 480 (c) 48000
  8. 8.Best estimate of 56 × 69? (a) 4200 (b) 42000 (c) 420
  9. 9.Best estimate of 46 × 50? (a) 25000 (b) 2500 (c) 250
  10. 10.Best estimate of 89 × 42? (a) 3600 (b) 360 (c) 36000
  11. 11.Best estimate of 320 + 841? (a) 1300 (b) 1100 (c) 900
  12. 12.Best estimate of 651 + 219? (a) 900 (b) 700 (c) 1100
  13. 13.Best estimate of 14 × 84? (a) 800 (b) 8000 (c) 80
  14. 14.Best estimate of 78 × 69? (a) 56000 (b) 560 (c) 5600
  15. 15.Best estimate of 846 + 381? (a) 1200 (b) 1400 (c) 1000
  16. 16.Best estimate of 36 × 43? (a) 16000 (b) 1600 (c) 160
  17. 17.Best estimate of 76 × 72? (a) 560 (b) 5600 (c) 56000
  18. 18.Best estimate of 333 + 342? (a) 600 (b) 400 (c) 800
  19. 19.Best estimate of 81 × 31? (a) 240 (b) 2400 (c) 24000
  20. 20.Best estimate of 326 + 747? (a) 1200 (b) 1000 (c) 800
  21. 21.Best estimate of 537 + 877? (a) 1400 (b) 1600 (c) 1200
  22. 22.Best estimate of 298 + 658? (a) 1000 (b) 800 (c) 1200
  23. 23.Best estimate of 700 + 369? (a) 900 (b) 1100 (c) 1300
  24. 24.Best estimate of 52 × 36? (a) 2000 (b) 200 (c) 20000
  25. 25.Best estimate of 311 + 160? (a) 700 (b) 300 (c) 500
  26. 26.Best estimate of 866 + 540? (a) 1600 (b) 1400 (c) 1200
  27. 27.Best estimate of 255 + 226? (a) 300 (b) 700 (c) 500
  28. 28.Best estimate of 827 + 661? (a) 1300 (b) 1700 (c) 1500
  29. 29.Best estimate of 726 + 383? (a) 1100 (b) 900 (c) 1300
  30. 30.Best estimate of 33 × 94? (a) 2700 (b) 270 (c) 27000
  31. 31.Best estimate of 53 × 24? (a) 100 (b) 10000 (c) 1000
  32. 32.Best estimate of 36 × 28? (a) 120 (b) 12000 (c) 1200
  33. 33.Best estimate of 19 × 42? (a) 80 (b) 800 (c) 8000
  34. 34.Best estimate of 67 × 76? (a) 5600 (b) 560 (c) 56000
  35. 35.Best estimate of 56 × 16? (a) 1200 (b) 120 (c) 12000
  36. 36.Best estimate of 21 × 51? (a) 1000 (b) 10000 (c) 100
  37. 37.Best estimate of 17 × 86? (a) 18000 (b) 180 (c) 1800
  38. 38.Best estimate of 96 × 86? (a) 90000 (b) 9000 (c) 900
  39. 39.Best estimate of 173 + 407? (a) 600 (b) 400 (c) 800
  40. 40.Best estimate of 33 × 16? (a) 60 (b) 600 (c) 6000

Answer key

  1. 1000
  2. 5600
  3. 1000
  4. 800
  5. 8100
  6. 5400
  7. 4800
  8. 4200
  9. 2500
  10. 3600
  11. 1100
  12. 900
  13. 800
  14. 5600
  15. 1200
  16. 1600
  17. 5600
  18. 600
  19. 2400
  20. 1000
  21. 1400
  22. 1000
  23. 1100
  24. 2000
  25. 500
  26. 1400
  27. 500
  28. 1500
  29. 1100
  30. 2700
  31. 1000
  32. 1200
  33. 800
  34. 5600
  35. 1200
  36. 1000
  37. 1800
  38. 9000
  39. 600
  40. 600

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