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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 871 · 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 139 + 875? (a) 1000 (b) 800 (c) 1200
  2. 2.Best estimate of 46 × 77? (a) 400 (b) 40000 (c) 4000
  3. 3.Best estimate of 83 × 90? (a) 72000 (b) 720 (c) 7200
  4. 4.Best estimate of 482 + 305? (a) 800 (b) 1000 (c) 600
  5. 5.Best estimate of 70 × 40? (a) 2800 (b) 28000 (c) 280
  6. 6.Best estimate of 681 + 658? (a) 1400 (b) 1200 (c) 1600
  7. 7.Best estimate of 24 × 42? (a) 800 (b) 80 (c) 8000
  8. 8.Best estimate of 96 × 96? (a) 1000 (b) 10000 (c) 100000
  9. 9.Best estimate of 278 + 606? (a) 700 (b) 900 (c) 1100
  10. 10.Best estimate of 78 × 81? (a) 640 (b) 6400 (c) 64000
  11. 11.Best estimate of 58 × 34? (a) 1800 (b) 180 (c) 18000
  12. 12.Best estimate of 22 × 16? (a) 40 (b) 4000 (c) 400
  13. 13.Best estimate of 136 + 657? (a) 1000 (b) 800 (c) 600
  14. 14.Best estimate of 724 + 269? (a) 1000 (b) 1200 (c) 800
  15. 15.Best estimate of 33 × 22? (a) 6000 (b) 60 (c) 600
  16. 16.Best estimate of 21 × 28? (a) 60 (b) 6000 (c) 600
  17. 17.Best estimate of 93 × 80? (a) 720 (b) 7200 (c) 72000
  18. 18.Best estimate of 60 × 93? (a) 54000 (b) 540 (c) 5400
  19. 19.Best estimate of 46 × 16? (a) 1000 (b) 10000 (c) 100
  20. 20.Best estimate of 335 + 820? (a) 1100 (b) 900 (c) 1300
  21. 21.Best estimate of 235 + 816? (a) 1000 (b) 1200 (c) 800
  22. 22.Best estimate of 98 × 86? (a) 900 (b) 90000 (c) 9000
  23. 23.Best estimate of 799 + 251? (a) 1300 (b) 900 (c) 1100
  24. 24.Best estimate of 26 × 71? (a) 21000 (b) 210 (c) 2100
  25. 25.Best estimate of 64 × 66? (a) 4200 (b) 42000 (c) 420
  26. 26.Best estimate of 88 × 38? (a) 36000 (b) 360 (c) 3600
  27. 27.Best estimate of 82 × 64? (a) 4800 (b) 480 (c) 48000
  28. 28.Best estimate of 72 × 84? (a) 560 (b) 5600 (c) 56000
  29. 29.Best estimate of 12 × 17? (a) 200 (b) 20 (c) 2000
  30. 30.Best estimate of 762 + 216? (a) 1200 (b) 800 (c) 1000
  31. 31.Best estimate of 591 + 492? (a) 1100 (b) 1300 (c) 900
  32. 32.Best estimate of 705 + 479? (a) 1400 (b) 1000 (c) 1200
  33. 33.Best estimate of 56 × 92? (a) 54000 (b) 540 (c) 5400
  34. 34.Best estimate of 710 + 274? (a) 1200 (b) 800 (c) 1000
  35. 35.Best estimate of 424 + 212? (a) 600 (b) 400 (c) 800
  36. 36.Best estimate of 80 × 83? (a) 64000 (b) 6400 (c) 640
  37. 37.Best estimate of 73 × 30? (a) 21000 (b) 2100 (c) 210
  38. 38.Best estimate of 26 × 94? (a) 27000 (b) 270 (c) 2700
  39. 39.Best estimate of 244 + 595? (a) 1000 (b) 600 (c) 800
  40. 40.Best estimate of 88 × 16? (a) 18000 (b) 180 (c) 1800

Answer key

  1. 1000
  2. 4000
  3. 7200
  4. 800
  5. 2800
  6. 1400
  7. 800
  8. 10000
  9. 900
  10. 6400
  11. 1800
  12. 400
  13. 800
  14. 1000
  15. 600
  16. 600
  17. 7200
  18. 5400
  19. 1000
  20. 1100
  21. 1000
  22. 9000
  23. 1100
  24. 2100
  25. 4200
  26. 3600
  27. 4800
  28. 5600
  29. 200
  30. 1000
  31. 1100
  32. 1200
  33. 5400
  34. 1000
  35. 600
  36. 6400
  37. 2100
  38. 2700
  39. 800
  40. 1800

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