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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 558 · 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 784 + 685? (a) 1300 (b) 1700 (c) 1500
  2. 2.Best estimate of 18 × 33? (a) 600 (b) 6000 (c) 60
  3. 3.Best estimate of 94 × 88? (a) 810 (b) 81000 (c) 8100
  4. 4.Best estimate of 81 × 86? (a) 720 (b) 7200 (c) 72000
  5. 5.Best estimate of 18 × 29? (a) 600 (b) 6000 (c) 60
  6. 6.Best estimate of 555 + 753? (a) 1200 (b) 1600 (c) 1400
  7. 7.Best estimate of 92 × 96? (a) 900 (b) 9000 (c) 90000
  8. 8.Best estimate of 48 × 52? (a) 2500 (b) 250 (c) 25000
  9. 9.Best estimate of 31 × 20? (a) 60 (b) 6000 (c) 600
  10. 10.Best estimate of 53 × 44? (a) 20000 (b) 200 (c) 2000
  11. 11.Best estimate of 51 × 83? (a) 400 (b) 4000 (c) 40000
  12. 12.Best estimate of 79 × 36? (a) 3200 (b) 320 (c) 32000
  13. 13.Best estimate of 127 + 367? (a) 300 (b) 500 (c) 700
  14. 14.Best estimate of 193 + 378? (a) 800 (b) 400 (c) 600
  15. 15.Best estimate of 56 × 58? (a) 3600 (b) 360 (c) 36000
  16. 16.Best estimate of 40 × 43? (a) 16000 (b) 160 (c) 1600
  17. 17.Best estimate of 90 × 12? (a) 90 (b) 9000 (c) 900
  18. 18.Best estimate of 38 × 52? (a) 200 (b) 2000 (c) 20000
  19. 19.Best estimate of 14 × 82? (a) 8000 (b) 80 (c) 800
  20. 20.Best estimate of 713 + 416? (a) 1300 (b) 900 (c) 1100
  21. 21.Best estimate of 20 × 96? (a) 20000 (b) 2000 (c) 200
  22. 22.Best estimate of 79 × 90? (a) 7200 (b) 72000 (c) 720
  23. 23.Best estimate of 69 × 74? (a) 4900 (b) 490 (c) 49000
  24. 24.Best estimate of 90 × 46? (a) 4500 (b) 45000 (c) 450
  25. 25.Best estimate of 531 + 816? (a) 1500 (b) 1100 (c) 1300
  26. 26.Best estimate of 746 + 277? (a) 1000 (b) 800 (c) 1200
  27. 27.Best estimate of 838 + 498? (a) 1300 (b) 1500 (c) 1100
  28. 28.Best estimate of 432 + 463? (a) 1100 (b) 900 (c) 700
  29. 29.Best estimate of 158 + 756? (a) 1200 (b) 1000 (c) 800
  30. 30.Best estimate of 98 × 88? (a) 9000 (b) 900 (c) 90000
  31. 31.Best estimate of 47 × 77? (a) 40000 (b) 400 (c) 4000
  32. 32.Best estimate of 24 × 33? (a) 60 (b) 600 (c) 6000
  33. 33.Best estimate of 16 × 31? (a) 60 (b) 6000 (c) 600
  34. 34.Best estimate of 545 + 355? (a) 1100 (b) 900 (c) 700
  35. 35.Best estimate of 56 × 88? (a) 5400 (b) 540 (c) 54000
  36. 36.Best estimate of 561 + 180? (a) 1000 (b) 600 (c) 800
  37. 37.Best estimate of 619 + 686? (a) 1500 (b) 1300 (c) 1100
  38. 38.Best estimate of 669 + 259? (a) 1200 (b) 800 (c) 1000
  39. 39.Best estimate of 93 × 23? (a) 18000 (b) 1800 (c) 180
  40. 40.Best estimate of 31 × 69? (a) 21000 (b) 2100 (c) 210

Answer key

  1. 1500
  2. 600
  3. 8100
  4. 7200
  5. 600
  6. 1400
  7. 9000
  8. 2500
  9. 600
  10. 2000
  11. 4000
  12. 3200
  13. 500
  14. 600
  15. 3600
  16. 1600
  17. 900
  18. 2000
  19. 800
  20. 1100
  21. 2000
  22. 7200
  23. 4900
  24. 4500
  25. 1300
  26. 1000
  27. 1300
  28. 900
  29. 1000
  30. 9000
  31. 4000
  32. 600
  33. 600
  34. 900
  35. 5400
  36. 800
  37. 1300
  38. 1000
  39. 1800
  40. 2100

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