← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 998 · 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 480 + 411? (a) 700 (b) 1100 (c) 900
  2. 2.Best estimate of 91 × 94? (a) 810 (b) 81000 (c) 8100
  3. 3.Best estimate of 97 × 89? (a) 9000 (b) 90000 (c) 900
  4. 4.Best estimate of 37 × 21? (a) 80 (b) 800 (c) 8000
  5. 5.Best estimate of 685 + 246? (a) 1100 (b) 900 (c) 700
  6. 6.Best estimate of 79 × 12? (a) 80 (b) 800 (c) 8000
  7. 7.Best estimate of 331 + 652? (a) 1000 (b) 800 (c) 1200
  8. 8.Best estimate of 21 × 39? (a) 8000 (b) 800 (c) 80
  9. 9.Best estimate of 382 + 863? (a) 1500 (b) 1100 (c) 1300
  10. 10.Best estimate of 21 × 36? (a) 80 (b) 800 (c) 8000
  11. 11.Best estimate of 22 × 40? (a) 800 (b) 80 (c) 8000
  12. 12.Best estimate of 583 + 277? (a) 1100 (b) 900 (c) 700
  13. 13.Best estimate of 66 × 14? (a) 700 (b) 70 (c) 7000
  14. 14.Best estimate of 89 × 52? (a) 45000 (b) 450 (c) 4500
  15. 15.Best estimate of 21 × 27? (a) 600 (b) 6000 (c) 60
  16. 16.Best estimate of 20 × 31? (a) 60 (b) 600 (c) 6000
  17. 17.Best estimate of 66 × 13? (a) 700 (b) 7000 (c) 70
  18. 18.Best estimate of 835 + 742? (a) 1300 (b) 1700 (c) 1500
  19. 19.Best estimate of 56 × 31? (a) 18000 (b) 1800 (c) 180
  20. 20.Best estimate of 742 + 475? (a) 1400 (b) 1000 (c) 1200
  21. 21.Best estimate of 441 + 131? (a) 500 (b) 700 (c) 300
  22. 22.Best estimate of 49 × 58? (a) 3000 (b) 300 (c) 30000
  23. 23.Best estimate of 20 × 93? (a) 180 (b) 1800 (c) 18000
  24. 24.Best estimate of 855 + 196? (a) 900 (b) 1100 (c) 1300
  25. 25.Best estimate of 763 + 673? (a) 1700 (b) 1500 (c) 1300
  26. 26.Best estimate of 84 × 67? (a) 56000 (b) 5600 (c) 560
  27. 27.Best estimate of 32 × 90? (a) 2700 (b) 270 (c) 27000
  28. 28.Best estimate of 53 × 76? (a) 400 (b) 4000 (c) 40000
  29. 29.Best estimate of 745 + 458? (a) 1400 (b) 1000 (c) 1200
  30. 30.Best estimate of 801 + 403? (a) 1200 (b) 1000 (c) 1400
  31. 31.Best estimate of 89 × 66? (a) 6300 (b) 63000 (c) 630
  32. 32.Best estimate of 19 × 50? (a) 10000 (b) 100 (c) 1000
  33. 33.Best estimate of 36 × 54? (a) 20000 (b) 200 (c) 2000
  34. 34.Best estimate of 219 + 667? (a) 700 (b) 900 (c) 1100
  35. 35.Best estimate of 351 + 520? (a) 1100 (b) 900 (c) 700
  36. 36.Best estimate of 44 × 47? (a) 200 (b) 20000 (c) 2000
  37. 37.Best estimate of 584 + 216? (a) 1000 (b) 600 (c) 800
  38. 38.Best estimate of 656 + 707? (a) 1600 (b) 1400 (c) 1200
  39. 39.Best estimate of 661 + 464? (a) 1000 (b) 1400 (c) 1200
  40. 40.Best estimate of 323 + 484? (a) 800 (b) 600 (c) 1000

Answer key

  1. 900
  2. 8100
  3. 9000
  4. 800
  5. 900
  6. 800
  7. 1000
  8. 800
  9. 1300
  10. 800
  11. 800
  12. 900
  13. 700
  14. 4500
  15. 600
  16. 600
  17. 700
  18. 1500
  19. 1800
  20. 1200
  21. 500
  22. 3000
  23. 1800
  24. 1100
  25. 1500
  26. 5600
  27. 2700
  28. 4000
  29. 1200
  30. 1200
  31. 6300
  32. 1000
  33. 2000
  34. 900
  35. 900
  36. 2000
  37. 800
  38. 1400
  39. 1200
  40. 800

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