← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 60 · 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 20 × 98? (a) 2000 (b) 200 (c) 20000
  2. 2.Best estimate of 748 + 211? (a) 1100 (b) 900 (c) 700
  3. 3.Best estimate of 679 + 843? (a) 1700 (b) 1500 (c) 1300
  4. 4.Best estimate of 601 + 284? (a) 1100 (b) 900 (c) 700
  5. 5.Best estimate of 336 + 437? (a) 900 (b) 500 (c) 700
  6. 6.Best estimate of 161 + 591? (a) 600 (b) 1000 (c) 800
  7. 7.Best estimate of 27 × 54? (a) 1500 (b) 150 (c) 15000
  8. 8.Best estimate of 448 + 513? (a) 700 (b) 1100 (c) 900
  9. 9.Best estimate of 611 + 156? (a) 1000 (b) 600 (c) 800
  10. 10.Best estimate of 59 × 12? (a) 600 (b) 6000 (c) 60
  11. 11.Best estimate of 98 × 19? (a) 2000 (b) 20000 (c) 200
  12. 12.Best estimate of 33 × 51? (a) 150 (b) 15000 (c) 1500
  13. 13.Best estimate of 327 + 464? (a) 600 (b) 800 (c) 1000
  14. 14.Best estimate of 875 + 357? (a) 1300 (b) 1500 (c) 1100
  15. 15.Best estimate of 24 × 23? (a) 40 (b) 400 (c) 4000
  16. 16.Best estimate of 91 × 13? (a) 900 (b) 9000 (c) 90
  17. 17.Best estimate of 27 × 41? (a) 1200 (b) 12000 (c) 120
  18. 18.Best estimate of 623 + 854? (a) 1700 (b) 1500 (c) 1300
  19. 19.Best estimate of 18 × 43? (a) 8000 (b) 800 (c) 80
  20. 20.Best estimate of 872 + 644? (a) 1700 (b) 1500 (c) 1300
  21. 21.Best estimate of 412 + 226? (a) 400 (b) 800 (c) 600
  22. 22.Best estimate of 171 + 766? (a) 1000 (b) 1200 (c) 800
  23. 23.Best estimate of 24 × 68? (a) 1400 (b) 14000 (c) 140
  24. 24.Best estimate of 14 × 51? (a) 500 (b) 5000 (c) 50
  25. 25.Best estimate of 194 + 139? (a) 300 (b) 500 (c) 100
  26. 26.Best estimate of 46 × 90? (a) 4500 (b) 450 (c) 45000
  27. 27.Best estimate of 62 × 26? (a) 18000 (b) 180 (c) 1800
  28. 28.Best estimate of 64 × 94? (a) 54000 (b) 540 (c) 5400
  29. 29.Best estimate of 774 + 461? (a) 1500 (b) 1300 (c) 1100
  30. 30.Best estimate of 281 + 386? (a) 900 (b) 700 (c) 500
  31. 31.Best estimate of 22 × 71? (a) 14000 (b) 1400 (c) 140
  32. 32.Best estimate of 712 + 676? (a) 1400 (b) 1200 (c) 1600
  33. 33.Best estimate of 467 + 805? (a) 1300 (b) 1500 (c) 1100
  34. 34.Best estimate of 315 + 797? (a) 1100 (b) 1300 (c) 900
  35. 35.Best estimate of 18 × 42? (a) 800 (b) 8000 (c) 80
  36. 36.Best estimate of 711 + 800? (a) 1700 (b) 1300 (c) 1500
  37. 37.Best estimate of 30 × 38? (a) 1200 (b) 120 (c) 12000
  38. 38.Best estimate of 519 + 146? (a) 600 (b) 800 (c) 400
  39. 39.Best estimate of 41 × 89? (a) 3600 (b) 360 (c) 36000
  40. 40.Best estimate of 710 + 290? (a) 800 (b) 1000 (c) 1200

Answer key

  1. 2000
  2. 900
  3. 1500
  4. 900
  5. 700
  6. 800
  7. 1500
  8. 900
  9. 800
  10. 600
  11. 2000
  12. 1500
  13. 800
  14. 1300
  15. 400
  16. 900
  17. 1200
  18. 1500
  19. 800
  20. 1500
  21. 600
  22. 1000
  23. 1400
  24. 500
  25. 300
  26. 4500
  27. 1800
  28. 5400
  29. 1300
  30. 700
  31. 1400
  32. 1400
  33. 1300
  34. 1100
  35. 800
  36. 1500
  37. 1200
  38. 600
  39. 3600
  40. 1000

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