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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 94 · 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 375 + 719? (a) 900 (b) 1300 (c) 1100
  2. 2.Best estimate of 338 + 272? (a) 600 (b) 400 (c) 800
  3. 3.Best estimate of 53 × 36? (a) 2000 (b) 200 (c) 20000
  4. 4.Best estimate of 34 × 57? (a) 180 (b) 18000 (c) 1800
  5. 5.Best estimate of 813 + 530? (a) 1300 (b) 1500 (c) 1100
  6. 6.Best estimate of 14 × 81? (a) 8000 (b) 800 (c) 80
  7. 7.Best estimate of 548 + 228? (a) 900 (b) 500 (c) 700
  8. 8.Best estimate of 587 + 337? (a) 700 (b) 900 (c) 1100
  9. 9.Best estimate of 12 × 88? (a) 9000 (b) 90 (c) 900
  10. 10.Best estimate of 413 + 262? (a) 900 (b) 700 (c) 500
  11. 11.Best estimate of 148 + 356? (a) 700 (b) 300 (c) 500
  12. 12.Best estimate of 20 × 56? (a) 12000 (b) 1200 (c) 120
  13. 13.Best estimate of 451 + 310? (a) 1000 (b) 600 (c) 800
  14. 14.Best estimate of 36 × 16? (a) 800 (b) 8000 (c) 80
  15. 15.Best estimate of 324 + 654? (a) 1200 (b) 800 (c) 1000
  16. 16.Best estimate of 22 × 20? (a) 400 (b) 40 (c) 4000
  17. 17.Best estimate of 346 + 188? (a) 500 (b) 300 (c) 700
  18. 18.Best estimate of 264 + 809? (a) 1300 (b) 1100 (c) 900
  19. 19.Best estimate of 27 × 46? (a) 150 (b) 1500 (c) 15000
  20. 20.Best estimate of 64 × 46? (a) 3000 (b) 300 (c) 30000
  21. 21.Best estimate of 48 × 41? (a) 20000 (b) 2000 (c) 200
  22. 22.Best estimate of 365 + 732? (a) 1100 (b) 900 (c) 1300
  23. 23.Best estimate of 48 × 57? (a) 3000 (b) 300 (c) 30000
  24. 24.Best estimate of 41 × 36? (a) 16000 (b) 160 (c) 1600
  25. 25.Best estimate of 76 × 12? (a) 800 (b) 80 (c) 8000
  26. 26.Best estimate of 87 × 86? (a) 8100 (b) 810 (c) 81000
  27. 27.Best estimate of 43 × 16? (a) 800 (b) 8000 (c) 80
  28. 28.Best estimate of 31 × 42? (a) 12000 (b) 120 (c) 1200
  29. 29.Best estimate of 259 + 354? (a) 700 (b) 900 (c) 500
  30. 30.Best estimate of 54 × 46? (a) 250 (b) 2500 (c) 25000
  31. 31.Best estimate of 96 × 16? (a) 200 (b) 20000 (c) 2000
  32. 32.Best estimate of 20 × 94? (a) 1800 (b) 180 (c) 18000
  33. 33.Best estimate of 62 × 46? (a) 3000 (b) 30000 (c) 300
  34. 34.Best estimate of 21 × 60? (a) 120 (b) 12000 (c) 1200
  35. 35.Best estimate of 92 × 93? (a) 810 (b) 81000 (c) 8100
  36. 36.Best estimate of 16 × 36? (a) 80 (b) 800 (c) 8000
  37. 37.Best estimate of 96 × 84? (a) 800 (b) 8000 (c) 80000
  38. 38.Best estimate of 66 × 51? (a) 350 (b) 35000 (c) 3500
  39. 39.Best estimate of 57 × 19? (a) 12000 (b) 120 (c) 1200
  40. 40.Best estimate of 207 + 587? (a) 800 (b) 1000 (c) 600

Answer key

  1. 1100
  2. 600
  3. 2000
  4. 1800
  5. 1300
  6. 800
  7. 700
  8. 900
  9. 900
  10. 700
  11. 500
  12. 1200
  13. 800
  14. 800
  15. 1000
  16. 400
  17. 500
  18. 1100
  19. 1500
  20. 3000
  21. 2000
  22. 1100
  23. 3000
  24. 1600
  25. 800
  26. 8100
  27. 800
  28. 1200
  29. 700
  30. 2500
  31. 2000
  32. 1800
  33. 3000
  34. 1200
  35. 8100
  36. 800
  37. 8000
  38. 3500
  39. 1200
  40. 800

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