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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 847 · 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 53 × 67? (a) 3500 (b) 350 (c) 35000
  2. 2.Best estimate of 74 × 52? (a) 350 (b) 35000 (c) 3500
  3. 3.Best estimate of 80 × 50? (a) 4000 (b) 400 (c) 40000
  4. 4.Best estimate of 26 × 32? (a) 9000 (b) 900 (c) 90
  5. 5.Best estimate of 87 × 66? (a) 6300 (b) 630 (c) 63000
  6. 6.Best estimate of 70 × 48? (a) 35000 (b) 350 (c) 3500
  7. 7.Best estimate of 21 × 84? (a) 1600 (b) 160 (c) 16000
  8. 8.Best estimate of 872 + 874? (a) 2000 (b) 1800 (c) 1600
  9. 9.Best estimate of 68 × 89? (a) 630 (b) 63000 (c) 6300
  10. 10.Best estimate of 52 × 86? (a) 4500 (b) 45000 (c) 450
  11. 11.Best estimate of 46 × 61? (a) 3000 (b) 300 (c) 30000
  12. 12.Best estimate of 863 + 204? (a) 1100 (b) 900 (c) 1300
  13. 13.Best estimate of 172 + 133? (a) 300 (b) 100 (c) 500
  14. 14.Best estimate of 20 × 66? (a) 140 (b) 14000 (c) 1400
  15. 15.Best estimate of 94 × 13? (a) 900 (b) 9000 (c) 90
  16. 16.Best estimate of 264 + 879? (a) 1000 (b) 1400 (c) 1200
  17. 17.Best estimate of 502 + 320? (a) 1000 (b) 800 (c) 600
  18. 18.Best estimate of 29 × 32? (a) 9000 (b) 900 (c) 90
  19. 19.Best estimate of 73 × 53? (a) 35000 (b) 3500 (c) 350
  20. 20.Best estimate of 795 + 462? (a) 1300 (b) 1500 (c) 1100
  21. 21.Best estimate of 867 + 517? (a) 1400 (b) 1200 (c) 1600
  22. 22.Best estimate of 68 × 51? (a) 35000 (b) 3500 (c) 350
  23. 23.Best estimate of 551 + 666? (a) 1300 (b) 1500 (c) 1100
  24. 24.Best estimate of 502 + 858? (a) 1400 (b) 1200 (c) 1600
  25. 25.Best estimate of 351 + 406? (a) 800 (b) 600 (c) 1000
  26. 26.Best estimate of 543 + 173? (a) 900 (b) 700 (c) 500
  27. 27.Best estimate of 53 × 89? (a) 450 (b) 45000 (c) 4500
  28. 28.Best estimate of 149 + 726? (a) 800 (b) 600 (c) 1000
  29. 29.Best estimate of 759 + 596? (a) 1400 (b) 1200 (c) 1600
  30. 30.Best estimate of 24 × 33? (a) 6000 (b) 600 (c) 60
  31. 31.Best estimate of 252 + 848? (a) 1300 (b) 1100 (c) 900
  32. 32.Best estimate of 863 + 775? (a) 1500 (b) 1900 (c) 1700
  33. 33.Best estimate of 668 + 148? (a) 1000 (b) 800 (c) 600
  34. 34.Best estimate of 33 × 98? (a) 3000 (b) 30000 (c) 300
  35. 35.Best estimate of 22 × 64? (a) 12000 (b) 1200 (c) 120
  36. 36.Best estimate of 78 × 73? (a) 5600 (b) 560 (c) 56000
  37. 37.Best estimate of 53 × 78? (a) 400 (b) 40000 (c) 4000
  38. 38.Best estimate of 88 × 18? (a) 18000 (b) 180 (c) 1800
  39. 39.Best estimate of 18 × 43? (a) 8000 (b) 80 (c) 800
  40. 40.Best estimate of 22 × 63? (a) 120 (b) 12000 (c) 1200

Answer key

  1. 3500
  2. 3500
  3. 4000
  4. 900
  5. 6300
  6. 3500
  7. 1600
  8. 1800
  9. 6300
  10. 4500
  11. 3000
  12. 1100
  13. 300
  14. 1400
  15. 900
  16. 1200
  17. 800
  18. 900
  19. 3500
  20. 1300
  21. 1400
  22. 3500
  23. 1300
  24. 1400
  25. 800
  26. 700
  27. 4500
  28. 800
  29. 1400
  30. 600
  31. 1100
  32. 1700
  33. 800
  34. 3000
  35. 1200
  36. 5600
  37. 4000
  38. 1800
  39. 800
  40. 1200

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