← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 86 · 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 258 + 148? (a) 400 (b) 200 (c) 600
  2. 2.Best estimate of 822 + 478? (a) 1100 (b) 1500 (c) 1300
  3. 3.Best estimate of 40 × 32? (a) 120 (b) 12000 (c) 1200
  4. 4.Best estimate of 74 × 56? (a) 42000 (b) 4200 (c) 420
  5. 5.Best estimate of 863 + 207? (a) 900 (b) 1300 (c) 1100
  6. 6.Best estimate of 340 + 426? (a) 900 (b) 500 (c) 700
  7. 7.Best estimate of 127 + 706? (a) 1000 (b) 600 (c) 800
  8. 8.Best estimate of 70 × 76? (a) 5600 (b) 56000 (c) 560
  9. 9.Best estimate of 69 × 22? (a) 14000 (b) 1400 (c) 140
  10. 10.Best estimate of 292 + 797? (a) 900 (b) 1300 (c) 1100
  11. 11.Best estimate of 161 + 352? (a) 800 (b) 600 (c) 400
  12. 12.Best estimate of 843 + 561? (a) 1400 (b) 1600 (c) 1200
  13. 13.Best estimate of 32 × 28? (a) 9000 (b) 90 (c) 900
  14. 14.Best estimate of 143 + 715? (a) 1000 (b) 600 (c) 800
  15. 15.Best estimate of 157 + 738? (a) 900 (b) 700 (c) 1100
  16. 16.Best estimate of 61 × 27? (a) 1800 (b) 180 (c) 18000
  17. 17.Best estimate of 51 × 22? (a) 10000 (b) 1000 (c) 100
  18. 18.Best estimate of 60 × 20? (a) 12000 (b) 120 (c) 1200
  19. 19.Best estimate of 785 + 239? (a) 800 (b) 1200 (c) 1000
  20. 20.Best estimate of 176 + 430? (a) 400 (b) 800 (c) 600
  21. 21.Best estimate of 73 × 53? (a) 35000 (b) 350 (c) 3500
  22. 22.Best estimate of 29 × 18? (a) 6000 (b) 60 (c) 600
  23. 23.Best estimate of 505 + 717? (a) 1200 (b) 1000 (c) 1400
  24. 24.Best estimate of 216 + 769? (a) 1000 (b) 800 (c) 1200
  25. 25.Best estimate of 606 + 497? (a) 1100 (b) 1300 (c) 900
  26. 26.Best estimate of 43 × 29? (a) 12000 (b) 1200 (c) 120
  27. 27.Best estimate of 77 × 46? (a) 4000 (b) 400 (c) 40000
  28. 28.Best estimate of 46 × 42? (a) 20000 (b) 200 (c) 2000
  29. 29.Best estimate of 83 × 98? (a) 800 (b) 80000 (c) 8000
  30. 30.Best estimate of 777 + 295? (a) 1300 (b) 1100 (c) 900
  31. 31.Best estimate of 170 + 388? (a) 800 (b) 400 (c) 600
  32. 32.Best estimate of 330 + 156? (a) 300 (b) 500 (c) 700
  33. 33.Best estimate of 756 + 584? (a) 1600 (b) 1400 (c) 1200
  34. 34.Best estimate of 86 × 26? (a) 27000 (b) 2700 (c) 270
  35. 35.Best estimate of 76 × 98? (a) 800 (b) 8000 (c) 80000
  36. 36.Best estimate of 215 + 543? (a) 900 (b) 500 (c) 700
  37. 37.Best estimate of 90 × 87? (a) 81000 (b) 810 (c) 8100
  38. 38.Best estimate of 22 × 16? (a) 40 (b) 400 (c) 4000
  39. 39.Best estimate of 66 × 13? (a) 7000 (b) 700 (c) 70
  40. 40.Best estimate of 524 + 196? (a) 900 (b) 700 (c) 500

Answer key

  1. 400
  2. 1300
  3. 1200
  4. 4200
  5. 1100
  6. 700
  7. 800
  8. 5600
  9. 1400
  10. 1100
  11. 600
  12. 1400
  13. 900
  14. 800
  15. 900
  16. 1800
  17. 1000
  18. 1200
  19. 1000
  20. 600
  21. 3500
  22. 600
  23. 1200
  24. 1000
  25. 1100
  26. 1200
  27. 4000
  28. 2000
  29. 8000
  30. 1100
  31. 600
  32. 500
  33. 1400
  34. 2700
  35. 8000
  36. 700
  37. 8100
  38. 400
  39. 700
  40. 700

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