← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 151 · 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 18 × 88? (a) 1800 (b) 180 (c) 18000
  2. 2.Best estimate of 40 × 46? (a) 2000 (b) 200 (c) 20000
  3. 3.Best estimate of 16 × 30? (a) 600 (b) 60 (c) 6000
  4. 4.Best estimate of 222 + 332? (a) 300 (b) 500 (c) 700
  5. 5.Best estimate of 46 × 39? (a) 20000 (b) 2000 (c) 200
  6. 6.Best estimate of 203 + 380? (a) 400 (b) 600 (c) 800
  7. 7.Best estimate of 96 × 12? (a) 1000 (b) 10000 (c) 100
  8. 8.Best estimate of 352 + 436? (a) 800 (b) 1000 (c) 600
  9. 9.Best estimate of 454 + 411? (a) 700 (b) 1100 (c) 900
  10. 10.Best estimate of 178 + 219? (a) 600 (b) 200 (c) 400
  11. 11.Best estimate of 294 + 120? (a) 200 (b) 400 (c) 600
  12. 12.Best estimate of 263 + 208? (a) 700 (b) 500 (c) 300
  13. 13.Best estimate of 447 + 788? (a) 1400 (b) 1000 (c) 1200
  14. 14.Best estimate of 58 × 21? (a) 1200 (b) 12000 (c) 120
  15. 15.Best estimate of 418 + 259? (a) 500 (b) 700 (c) 900
  16. 16.Best estimate of 151 + 205? (a) 600 (b) 200 (c) 400
  17. 17.Best estimate of 73 × 36? (a) 28000 (b) 280 (c) 2800
  18. 18.Best estimate of 21 × 69? (a) 140 (b) 1400 (c) 14000
  19. 19.Best estimate of 17 × 72? (a) 1400 (b) 14000 (c) 140
  20. 20.Best estimate of 355 + 642? (a) 800 (b) 1000 (c) 1200
  21. 21.Best estimate of 720 + 634? (a) 1500 (b) 1300 (c) 1100
  22. 22.Best estimate of 742 + 182? (a) 700 (b) 900 (c) 1100
  23. 23.Best estimate of 372 + 829? (a) 1000 (b) 1200 (c) 1400
  24. 24.Best estimate of 661 + 486? (a) 1000 (b) 1400 (c) 1200
  25. 25.Best estimate of 94 × 39? (a) 3600 (b) 360 (c) 36000
  26. 26.Best estimate of 729 + 380? (a) 1100 (b) 1300 (c) 900
  27. 27.Best estimate of 726 + 847? (a) 1300 (b) 1500 (c) 1700
  28. 28.Best estimate of 728 + 700? (a) 1200 (b) 1600 (c) 1400
  29. 29.Best estimate of 97 × 49? (a) 5000 (b) 50000 (c) 500
  30. 30.Best estimate of 754 + 175? (a) 1200 (b) 800 (c) 1000
  31. 31.Best estimate of 731 + 248? (a) 700 (b) 900 (c) 1100
  32. 32.Best estimate of 86 × 96? (a) 90000 (b) 900 (c) 9000
  33. 33.Best estimate of 83 × 93? (a) 7200 (b) 72000 (c) 720
  34. 34.Best estimate of 77 × 56? (a) 48000 (b) 480 (c) 4800
  35. 35.Best estimate of 29 × 21? (a) 60 (b) 6000 (c) 600
  36. 36.Best estimate of 372 + 799? (a) 1200 (b) 1000 (c) 1400
  37. 37.Best estimate of 261 + 446? (a) 700 (b) 900 (c) 500
  38. 38.Best estimate of 72 × 36? (a) 28000 (b) 280 (c) 2800
  39. 39.Best estimate of 539 + 596? (a) 1100 (b) 900 (c) 1300
  40. 40.Best estimate of 76 × 81? (a) 6400 (b) 640 (c) 64000

Answer key

  1. 1800
  2. 2000
  3. 600
  4. 500
  5. 2000
  6. 600
  7. 1000
  8. 800
  9. 900
  10. 400
  11. 400
  12. 500
  13. 1200
  14. 1200
  15. 700
  16. 400
  17. 2800
  18. 1400
  19. 1400
  20. 1000
  21. 1300
  22. 900
  23. 1200
  24. 1200
  25. 3600
  26. 1100
  27. 1500
  28. 1400
  29. 5000
  30. 1000
  31. 900
  32. 9000
  33. 7200
  34. 4800
  35. 600
  36. 1200
  37. 700
  38. 2800
  39. 1100
  40. 6400

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