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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 282 · 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 158 + 845? (a) 1000 (b) 1200 (c) 800
  2. 2.Best estimate of 61 × 96? (a) 60000 (b) 6000 (c) 600
  3. 3.Best estimate of 84 × 92? (a) 72000 (b) 7200 (c) 720
  4. 4.Best estimate of 92 × 32? (a) 270 (b) 27000 (c) 2700
  5. 5.Best estimate of 276 + 796? (a) 900 (b) 1100 (c) 1300
  6. 6.Best estimate of 26 × 86? (a) 27000 (b) 270 (c) 2700
  7. 7.Best estimate of 613 + 317? (a) 1100 (b) 700 (c) 900
  8. 8.Best estimate of 76 × 79? (a) 6400 (b) 64000 (c) 640
  9. 9.Best estimate of 826 + 387? (a) 1400 (b) 1000 (c) 1200
  10. 10.Best estimate of 332 + 652? (a) 1200 (b) 800 (c) 1000
  11. 11.Best estimate of 309 + 355? (a) 500 (b) 700 (c) 900
  12. 12.Best estimate of 62 × 90? (a) 54000 (b) 5400 (c) 540
  13. 13.Best estimate of 42 × 51? (a) 2000 (b) 20000 (c) 200
  14. 14.Best estimate of 307 + 536? (a) 1000 (b) 800 (c) 600
  15. 15.Best estimate of 46 × 56? (a) 30000 (b) 300 (c) 3000
  16. 16.Best estimate of 572 + 261? (a) 900 (b) 1100 (c) 700
  17. 17.Best estimate of 17 × 22? (a) 4000 (b) 40 (c) 400
  18. 18.Best estimate of 69 × 38? (a) 2800 (b) 280 (c) 28000
  19. 19.Best estimate of 756 + 812? (a) 1400 (b) 1800 (c) 1600
  20. 20.Best estimate of 744 + 649? (a) 1100 (b) 1500 (c) 1300
  21. 21.Best estimate of 433 + 498? (a) 900 (b) 1100 (c) 700
  22. 22.Best estimate of 73 × 52? (a) 3500 (b) 350 (c) 35000
  23. 23.Best estimate of 665 + 542? (a) 1400 (b) 1000 (c) 1200
  24. 24.Best estimate of 723 + 465? (a) 1400 (b) 1200 (c) 1000
  25. 25.Best estimate of 14 × 41? (a) 400 (b) 4000 (c) 40
  26. 26.Best estimate of 83 × 13? (a) 80 (b) 800 (c) 8000
  27. 27.Best estimate of 19 × 46? (a) 100 (b) 1000 (c) 10000
  28. 28.Best estimate of 72 × 86? (a) 630 (b) 63000 (c) 6300
  29. 29.Best estimate of 636 + 742? (a) 1300 (b) 1100 (c) 1500
  30. 30.Best estimate of 80 × 64? (a) 4800 (b) 48000 (c) 480
  31. 31.Best estimate of 657 + 677? (a) 1400 (b) 1200 (c) 1600
  32. 32.Best estimate of 483 + 837? (a) 1500 (b) 1300 (c) 1100
  33. 33.Best estimate of 82 × 12? (a) 80 (b) 800 (c) 8000
  34. 34.Best estimate of 36 × 40? (a) 160 (b) 1600 (c) 16000
  35. 35.Best estimate of 73 × 24? (a) 1400 (b) 140 (c) 14000
  36. 36.Best estimate of 653 + 556? (a) 1100 (b) 1500 (c) 1300
  37. 37.Best estimate of 712 + 700? (a) 1400 (b) 1200 (c) 1600
  38. 38.Best estimate of 22 × 61? (a) 1200 (b) 12000 (c) 120
  39. 39.Best estimate of 21 × 26? (a) 600 (b) 6000 (c) 60
  40. 40.Best estimate of 191 + 376? (a) 600 (b) 400 (c) 800

Answer key

  1. 1000
  2. 6000
  3. 7200
  4. 2700
  5. 1100
  6. 2700
  7. 900
  8. 6400
  9. 1200
  10. 1000
  11. 700
  12. 5400
  13. 2000
  14. 800
  15. 3000
  16. 900
  17. 400
  18. 2800
  19. 1600
  20. 1300
  21. 900
  22. 3500
  23. 1200
  24. 1200
  25. 400
  26. 800
  27. 1000
  28. 6300
  29. 1300
  30. 4800
  31. 1400
  32. 1300
  33. 800
  34. 1600
  35. 1400
  36. 1300
  37. 1400
  38. 1200
  39. 600
  40. 600

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