← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 973 · 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 31 × 71? (a) 2100 (b) 210 (c) 21000
  2. 2.Best estimate of 281 + 144? (a) 400 (b) 600 (c) 200
  3. 3.Best estimate of 851 + 607? (a) 1500 (b) 1700 (c) 1300
  4. 4.Best estimate of 17 × 42? (a) 800 (b) 80 (c) 8000
  5. 5.Best estimate of 715 + 256? (a) 800 (b) 1200 (c) 1000
  6. 6.Best estimate of 54 × 28? (a) 150 (b) 15000 (c) 1500
  7. 7.Best estimate of 86 × 57? (a) 54000 (b) 5400 (c) 540
  8. 8.Best estimate of 82 × 31? (a) 2400 (b) 24000 (c) 240
  9. 9.Best estimate of 366 + 807? (a) 1000 (b) 1200 (c) 1400
  10. 10.Best estimate of 507 + 396? (a) 900 (b) 1100 (c) 700
  11. 11.Best estimate of 49 × 58? (a) 30000 (b) 3000 (c) 300
  12. 12.Best estimate of 171 + 764? (a) 800 (b) 1200 (c) 1000
  13. 13.Best estimate of 66 × 88? (a) 63000 (b) 6300 (c) 630
  14. 14.Best estimate of 98 × 76? (a) 800 (b) 8000 (c) 80000
  15. 15.Best estimate of 764 + 819? (a) 1600 (b) 1800 (c) 1400
  16. 16.Best estimate of 375 + 866? (a) 1500 (b) 1300 (c) 1100
  17. 17.Best estimate of 688 + 520? (a) 1200 (b) 1000 (c) 1400
  18. 18.Best estimate of 29 × 98? (a) 300 (b) 30000 (c) 3000
  19. 19.Best estimate of 789 + 532? (a) 1300 (b) 1500 (c) 1100
  20. 20.Best estimate of 636 + 638? (a) 1000 (b) 1200 (c) 1400
  21. 21.Best estimate of 415 + 375? (a) 1000 (b) 800 (c) 600
  22. 22.Best estimate of 672 + 462? (a) 1200 (b) 1400 (c) 1000
  23. 23.Best estimate of 767 + 834? (a) 1800 (b) 1400 (c) 1600
  24. 24.Best estimate of 372 + 152? (a) 600 (b) 400 (c) 800
  25. 25.Best estimate of 268 + 339? (a) 800 (b) 400 (c) 600
  26. 26.Best estimate of 70 × 49? (a) 3500 (b) 35000 (c) 350
  27. 27.Best estimate of 66 × 30? (a) 210 (b) 2100 (c) 21000
  28. 28.Best estimate of 788 + 771? (a) 1600 (b) 1800 (c) 1400
  29. 29.Best estimate of 644 + 120? (a) 500 (b) 700 (c) 900
  30. 30.Best estimate of 68 × 20? (a) 14000 (b) 1400 (c) 140
  31. 31.Best estimate of 349 + 390? (a) 900 (b) 500 (c) 700
  32. 32.Best estimate of 807 + 384? (a) 1400 (b) 1000 (c) 1200
  33. 33.Best estimate of 760 + 498? (a) 1100 (b) 1300 (c) 1500
  34. 34.Best estimate of 228 + 813? (a) 1000 (b) 800 (c) 1200
  35. 35.Best estimate of 38 × 58? (a) 24000 (b) 2400 (c) 240
  36. 36.Best estimate of 36 × 24? (a) 80 (b) 800 (c) 8000
  37. 37.Best estimate of 389 + 664? (a) 1100 (b) 1300 (c) 900
  38. 38.Best estimate of 153 + 559? (a) 1000 (b) 600 (c) 800
  39. 39.Best estimate of 62 × 32? (a) 180 (b) 1800 (c) 18000
  40. 40.Best estimate of 16 × 32? (a) 600 (b) 60 (c) 6000

Answer key

  1. 2100
  2. 400
  3. 1500
  4. 800
  5. 1000
  6. 1500
  7. 5400
  8. 2400
  9. 1200
  10. 900
  11. 3000
  12. 1000
  13. 6300
  14. 8000
  15. 1600
  16. 1300
  17. 1200
  18. 3000
  19. 1300
  20. 1200
  21. 800
  22. 1200
  23. 1600
  24. 600
  25. 600
  26. 3500
  27. 2100
  28. 1600
  29. 700
  30. 1400
  31. 700
  32. 1200
  33. 1300
  34. 1000
  35. 2400
  36. 800
  37. 1100
  38. 800
  39. 1800
  40. 600

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths