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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 776 · 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 848 + 184? (a) 800 (b) 1000 (c) 1200
  2. 2.Best estimate of 60 × 20? (a) 12000 (b) 120 (c) 1200
  3. 3.Best estimate of 58 × 86? (a) 540 (b) 5400 (c) 54000
  4. 4.Best estimate of 26 × 71? (a) 2100 (b) 210 (c) 21000
  5. 5.Best estimate of 96 × 43? (a) 400 (b) 4000 (c) 40000
  6. 6.Best estimate of 26 × 19? (a) 600 (b) 60 (c) 6000
  7. 7.Best estimate of 600 + 154? (a) 800 (b) 1000 (c) 600
  8. 8.Best estimate of 535 + 126? (a) 600 (b) 400 (c) 800
  9. 9.Best estimate of 98 × 53? (a) 500 (b) 50000 (c) 5000
  10. 10.Best estimate of 29 × 67? (a) 2100 (b) 21000 (c) 210
  11. 11.Best estimate of 508 + 414? (a) 1100 (b) 700 (c) 900
  12. 12.Best estimate of 364 + 675? (a) 1100 (b) 900 (c) 1300
  13. 13.Best estimate of 151 + 183? (a) 400 (b) 600 (c) 200
  14. 14.Best estimate of 53 × 31? (a) 150 (b) 15000 (c) 1500
  15. 15.Best estimate of 747 + 711? (a) 1600 (b) 1200 (c) 1400
  16. 16.Best estimate of 365 + 764? (a) 1400 (b) 1000 (c) 1200
  17. 17.Best estimate of 653 + 698? (a) 1600 (b) 1400 (c) 1200
  18. 18.Best estimate of 46 × 57? (a) 30000 (b) 3000 (c) 300
  19. 19.Best estimate of 60 × 87? (a) 5400 (b) 540 (c) 54000
  20. 20.Best estimate of 41 × 80? (a) 320 (b) 3200 (c) 32000
  21. 21.Best estimate of 57 × 21? (a) 1200 (b) 12000 (c) 120
  22. 22.Best estimate of 827 + 242? (a) 1000 (b) 800 (c) 1200
  23. 23.Best estimate of 21 × 76? (a) 160 (b) 16000 (c) 1600
  24. 24.Best estimate of 36 × 49? (a) 2000 (b) 200 (c) 20000
  25. 25.Best estimate of 46 × 50? (a) 2500 (b) 25000 (c) 250
  26. 26.Best estimate of 72 × 53? (a) 35000 (b) 3500 (c) 350
  27. 27.Best estimate of 848 + 294? (a) 1100 (b) 1300 (c) 900
  28. 28.Best estimate of 87 × 76? (a) 720 (b) 7200 (c) 72000
  29. 29.Best estimate of 411 + 174? (a) 800 (b) 600 (c) 400
  30. 30.Best estimate of 19 × 77? (a) 16000 (b) 160 (c) 1600
  31. 31.Best estimate of 867 + 436? (a) 1500 (b) 1100 (c) 1300
  32. 32.Best estimate of 285 + 129? (a) 200 (b) 400 (c) 600
  33. 33.Best estimate of 33 × 18? (a) 6000 (b) 60 (c) 600
  34. 34.Best estimate of 23 × 76? (a) 160 (b) 16000 (c) 1600
  35. 35.Best estimate of 28 × 58? (a) 18000 (b) 180 (c) 1800
  36. 36.Best estimate of 62 × 60? (a) 3600 (b) 360 (c) 36000
  37. 37.Best estimate of 12 × 42? (a) 40 (b) 400 (c) 4000
  38. 38.Best estimate of 27 × 49? (a) 150 (b) 15000 (c) 1500
  39. 39.Best estimate of 36 × 32? (a) 12000 (b) 120 (c) 1200
  40. 40.Best estimate of 21 × 16? (a) 4000 (b) 40 (c) 400

Answer key

  1. 1000
  2. 1200
  3. 5400
  4. 2100
  5. 4000
  6. 600
  7. 800
  8. 600
  9. 5000
  10. 2100
  11. 900
  12. 1100
  13. 400
  14. 1500
  15. 1400
  16. 1200
  17. 1400
  18. 3000
  19. 5400
  20. 3200
  21. 1200
  22. 1000
  23. 1600
  24. 2000
  25. 2500
  26. 3500
  27. 1100
  28. 7200
  29. 600
  30. 1600
  31. 1300
  32. 400
  33. 600
  34. 1600
  35. 1800
  36. 3600
  37. 400
  38. 1500
  39. 1200
  40. 400

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