← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 82 · 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 98 × 44? (a) 40000 (b) 400 (c) 4000
  2. 2.Best estimate of 658 + 571? (a) 1300 (b) 1500 (c) 1100
  3. 3.Best estimate of 369 + 525? (a) 700 (b) 900 (c) 1100
  4. 4.Best estimate of 83 × 41? (a) 32000 (b) 3200 (c) 320
  5. 5.Best estimate of 54 × 71? (a) 3500 (b) 350 (c) 35000
  6. 6.Best estimate of 39 × 44? (a) 16000 (b) 1600 (c) 160
  7. 7.Best estimate of 43 × 23? (a) 800 (b) 8000 (c) 80
  8. 8.Best estimate of 194 + 593? (a) 800 (b) 600 (c) 1000
  9. 9.Best estimate of 168 + 414? (a) 800 (b) 600 (c) 400
  10. 10.Best estimate of 780 + 765? (a) 1800 (b) 1600 (c) 1400
  11. 11.Best estimate of 17 × 92? (a) 180 (b) 1800 (c) 18000
  12. 12.Best estimate of 142 + 464? (a) 600 (b) 800 (c) 400
  13. 13.Best estimate of 848 + 243? (a) 1200 (b) 800 (c) 1000
  14. 14.Best estimate of 214 + 744? (a) 700 (b) 900 (c) 1100
  15. 15.Best estimate of 737 + 434? (a) 1300 (b) 900 (c) 1100
  16. 16.Best estimate of 731 + 716? (a) 1200 (b) 1600 (c) 1400
  17. 17.Best estimate of 26 × 98? (a) 300 (b) 30000 (c) 3000
  18. 18.Best estimate of 385 + 719? (a) 1100 (b) 1300 (c) 900
  19. 19.Best estimate of 14 × 84? (a) 800 (b) 80 (c) 8000
  20. 20.Best estimate of 87 × 63? (a) 5400 (b) 54000 (c) 540
  21. 21.Best estimate of 40 × 29? (a) 1200 (b) 120 (c) 12000
  22. 22.Best estimate of 60 × 20? (a) 12000 (b) 120 (c) 1200
  23. 23.Best estimate of 74 × 51? (a) 35000 (b) 3500 (c) 350
  24. 24.Best estimate of 97 × 61? (a) 6000 (b) 60000 (c) 600
  25. 25.Best estimate of 66 × 71? (a) 490 (b) 49000 (c) 4900
  26. 26.Best estimate of 154 + 127? (a) 500 (b) 300 (c) 100
  27. 27.Best estimate of 618 + 203? (a) 600 (b) 800 (c) 1000
  28. 28.Best estimate of 795 + 429? (a) 1000 (b) 1400 (c) 1200
  29. 29.Best estimate of 655 + 794? (a) 1500 (b) 1700 (c) 1300
  30. 30.Best estimate of 89 × 44? (a) 36000 (b) 3600 (c) 360
  31. 31.Best estimate of 66 × 50? (a) 350 (b) 3500 (c) 35000
  32. 32.Best estimate of 419 + 174? (a) 400 (b) 600 (c) 800
  33. 33.Best estimate of 28 × 51? (a) 15000 (b) 1500 (c) 150
  34. 34.Best estimate of 597 + 623? (a) 1200 (b) 1000 (c) 1400
  35. 35.Best estimate of 523 + 458? (a) 1000 (b) 1200 (c) 800
  36. 36.Best estimate of 87 × 86? (a) 8100 (b) 81000 (c) 810
  37. 37.Best estimate of 23 × 37? (a) 8000 (b) 800 (c) 80
  38. 38.Best estimate of 19 × 90? (a) 18000 (b) 180 (c) 1800
  39. 39.Best estimate of 66 × 53? (a) 3500 (b) 350 (c) 35000
  40. 40.Best estimate of 746 + 570? (a) 1300 (b) 1500 (c) 1100

Answer key

  1. 4000
  2. 1300
  3. 900
  4. 3200
  5. 3500
  6. 1600
  7. 800
  8. 800
  9. 600
  10. 1600
  11. 1800
  12. 600
  13. 1000
  14. 900
  15. 1100
  16. 1400
  17. 3000
  18. 1100
  19. 800
  20. 5400
  21. 1200
  22. 1200
  23. 3500
  24. 6000
  25. 4900
  26. 300
  27. 800
  28. 1200
  29. 1500
  30. 3600
  31. 3500
  32. 600
  33. 1500
  34. 1200
  35. 1000
  36. 8100
  37. 800
  38. 1800
  39. 3500
  40. 1300

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