← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 153 · 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 46 × 30? (a) 150 (b) 1500 (c) 15000
  2. 2.Best estimate of 97 × 66? (a) 70000 (b) 7000 (c) 700
  3. 3.Best estimate of 97 × 19? (a) 200 (b) 2000 (c) 20000
  4. 4.Best estimate of 29 × 72? (a) 210 (b) 21000 (c) 2100
  5. 5.Best estimate of 333 + 775? (a) 1100 (b) 900 (c) 1300
  6. 6.Best estimate of 573 + 416? (a) 1000 (b) 800 (c) 1200
  7. 7.Best estimate of 63 × 58? (a) 36000 (b) 3600 (c) 360
  8. 8.Best estimate of 212 + 414? (a) 400 (b) 600 (c) 800
  9. 9.Best estimate of 78 × 23? (a) 160 (b) 16000 (c) 1600
  10. 10.Best estimate of 18 × 37? (a) 80 (b) 8000 (c) 800
  11. 11.Best estimate of 33 × 72? (a) 2100 (b) 210 (c) 21000
  12. 12.Best estimate of 30 × 37? (a) 1200 (b) 120 (c) 12000
  13. 13.Best estimate of 539 + 765? (a) 1100 (b) 1500 (c) 1300
  14. 14.Best estimate of 23 × 87? (a) 18000 (b) 1800 (c) 180
  15. 15.Best estimate of 351 + 382? (a) 600 (b) 800 (c) 1000
  16. 16.Best estimate of 46 × 82? (a) 4000 (b) 40000 (c) 400
  17. 17.Best estimate of 438 + 630? (a) 1000 (b) 800 (c) 1200
  18. 18.Best estimate of 64 × 54? (a) 3000 (b) 30000 (c) 300
  19. 19.Best estimate of 96 × 62? (a) 6000 (b) 60000 (c) 600
  20. 20.Best estimate of 16 × 91? (a) 180 (b) 18000 (c) 1800
  21. 21.Best estimate of 93 × 67? (a) 630 (b) 6300 (c) 63000
  22. 22.Best estimate of 675 + 511? (a) 1400 (b) 1200 (c) 1000
  23. 23.Best estimate of 36 × 21? (a) 8000 (b) 800 (c) 80
  24. 24.Best estimate of 58 × 71? (a) 4200 (b) 420 (c) 42000
  25. 25.Best estimate of 50 × 21? (a) 1000 (b) 10000 (c) 100
  26. 26.Best estimate of 696 + 253? (a) 1200 (b) 800 (c) 1000
  27. 27.Best estimate of 174 + 269? (a) 700 (b) 500 (c) 300
  28. 28.Best estimate of 50 × 29? (a) 15000 (b) 1500 (c) 150
  29. 29.Best estimate of 403 + 142? (a) 700 (b) 300 (c) 500
  30. 30.Best estimate of 365 + 254? (a) 700 (b) 500 (c) 900
  31. 31.Best estimate of 46 × 98? (a) 50000 (b) 500 (c) 5000
  32. 32.Best estimate of 13 × 43? (a) 40 (b) 400 (c) 4000
  33. 33.Best estimate of 610 + 151? (a) 1000 (b) 800 (c) 600
  34. 34.Best estimate of 712 + 279? (a) 1000 (b) 800 (c) 1200
  35. 35.Best estimate of 19 × 78? (a) 160 (b) 16000 (c) 1600
  36. 36.Best estimate of 43 × 86? (a) 36000 (b) 3600 (c) 360
  37. 37.Best estimate of 27 × 89? (a) 2700 (b) 270 (c) 27000
  38. 38.Best estimate of 26 × 51? (a) 150 (b) 15000 (c) 1500
  39. 39.Best estimate of 14 × 36? (a) 40 (b) 400 (c) 4000
  40. 40.Best estimate of 246 + 135? (a) 500 (b) 100 (c) 300

Answer key

  1. 1500
  2. 7000
  3. 2000
  4. 2100
  5. 1100
  6. 1000
  7. 3600
  8. 600
  9. 1600
  10. 800
  11. 2100
  12. 1200
  13. 1300
  14. 1800
  15. 800
  16. 4000
  17. 1000
  18. 3000
  19. 6000
  20. 1800
  21. 6300
  22. 1200
  23. 800
  24. 4200
  25. 1000
  26. 1000
  27. 500
  28. 1500
  29. 500
  30. 700
  31. 5000
  32. 400
  33. 800
  34. 1000
  35. 1600
  36. 3600
  37. 2700
  38. 1500
  39. 400
  40. 300

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