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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 602 · 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 545 + 360? (a) 700 (b) 900 (c) 1100
  2. 2.Best estimate of 365 + 668? (a) 1300 (b) 1100 (c) 900
  3. 3.Best estimate of 548 + 389? (a) 700 (b) 900 (c) 1100
  4. 4.Best estimate of 17 × 38? (a) 800 (b) 8000 (c) 80
  5. 5.Best estimate of 48 × 62? (a) 3000 (b) 30000 (c) 300
  6. 6.Best estimate of 76 × 46? (a) 40000 (b) 400 (c) 4000
  7. 7.Best estimate of 76 × 91? (a) 720 (b) 7200 (c) 72000
  8. 8.Best estimate of 249 + 481? (a) 700 (b) 900 (c) 500
  9. 9.Best estimate of 48 × 81? (a) 400 (b) 40000 (c) 4000
  10. 10.Best estimate of 777 + 468? (a) 1500 (b) 1100 (c) 1300
  11. 11.Best estimate of 129 + 748? (a) 800 (b) 1000 (c) 600
  12. 12.Best estimate of 714 + 483? (a) 1200 (b) 1000 (c) 1400
  13. 13.Best estimate of 92 × 28? (a) 2700 (b) 27000 (c) 270
  14. 14.Best estimate of 82 × 36? (a) 320 (b) 32000 (c) 3200
  15. 15.Best estimate of 58 × 97? (a) 6000 (b) 60000 (c) 600
  16. 16.Best estimate of 851 + 610? (a) 1300 (b) 1500 (c) 1700
  17. 17.Best estimate of 415 + 734? (a) 1100 (b) 1300 (c) 900
  18. 18.Best estimate of 264 + 523? (a) 1000 (b) 600 (c) 800
  19. 19.Best estimate of 44 × 38? (a) 160 (b) 1600 (c) 16000
  20. 20.Best estimate of 68 × 62? (a) 420 (b) 42000 (c) 4200
  21. 21.Best estimate of 61 × 13? (a) 60 (b) 6000 (c) 600
  22. 22.Best estimate of 39 × 46? (a) 2000 (b) 20000 (c) 200
  23. 23.Best estimate of 377 + 477? (a) 1100 (b) 900 (c) 700
  24. 24.Best estimate of 187 + 389? (a) 800 (b) 600 (c) 400
  25. 25.Best estimate of 172 + 426? (a) 400 (b) 800 (c) 600
  26. 26.Best estimate of 96 × 39? (a) 4000 (b) 40000 (c) 400
  27. 27.Best estimate of 230 + 729? (a) 700 (b) 1100 (c) 900
  28. 28.Best estimate of 93 × 40? (a) 3600 (b) 360 (c) 36000
  29. 29.Best estimate of 181 + 876? (a) 1100 (b) 1300 (c) 900
  30. 30.Best estimate of 97 × 64? (a) 60000 (b) 6000 (c) 600
  31. 31.Best estimate of 307 + 799? (a) 1300 (b) 1100 (c) 900
  32. 32.Best estimate of 90 × 59? (a) 54000 (b) 540 (c) 5400
  33. 33.Best estimate of 841 + 439? (a) 1000 (b) 1200 (c) 1400
  34. 34.Best estimate of 849 + 774? (a) 1800 (b) 1400 (c) 1600
  35. 35.Best estimate of 340 + 636? (a) 900 (b) 700 (c) 1100
  36. 36.Best estimate of 76 × 13? (a) 80 (b) 800 (c) 8000
  37. 37.Best estimate of 594 + 242? (a) 1000 (b) 800 (c) 600
  38. 38.Best estimate of 264 + 732? (a) 1200 (b) 800 (c) 1000
  39. 39.Best estimate of 705 + 666? (a) 1400 (b) 1600 (c) 1200
  40. 40.Best estimate of 716 + 244? (a) 900 (b) 1100 (c) 700

Answer key

  1. 900
  2. 1100
  3. 900
  4. 800
  5. 3000
  6. 4000
  7. 7200
  8. 700
  9. 4000
  10. 1300
  11. 800
  12. 1200
  13. 2700
  14. 3200
  15. 6000
  16. 1500
  17. 1100
  18. 800
  19. 1600
  20. 4200
  21. 600
  22. 2000
  23. 900
  24. 600
  25. 600
  26. 4000
  27. 900
  28. 3600
  29. 1100
  30. 6000
  31. 1100
  32. 5400
  33. 1200
  34. 1600
  35. 900
  36. 800
  37. 800
  38. 1000
  39. 1400
  40. 900

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