← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 349 · 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 48 × 20? (a) 10000 (b) 1000 (c) 100
  2. 2.Best estimate of 699 + 123? (a) 1000 (b) 600 (c) 800
  3. 3.Best estimate of 92 × 16? (a) 1800 (b) 18000 (c) 180
  4. 4.Best estimate of 154 + 451? (a) 900 (b) 500 (c) 700
  5. 5.Best estimate of 762 + 805? (a) 1600 (b) 1800 (c) 1400
  6. 6.Best estimate of 56 × 23? (a) 12000 (b) 120 (c) 1200
  7. 7.Best estimate of 22 × 32? (a) 6000 (b) 600 (c) 60
  8. 8.Best estimate of 39 × 40? (a) 1600 (b) 16000 (c) 160
  9. 9.Best estimate of 24 × 88? (a) 18000 (b) 1800 (c) 180
  10. 10.Best estimate of 60 × 86? (a) 5400 (b) 54000 (c) 540
  11. 11.Best estimate of 57 × 51? (a) 3000 (b) 300 (c) 30000
  12. 12.Best estimate of 80 × 24? (a) 16000 (b) 160 (c) 1600
  13. 13.Best estimate of 735 + 343? (a) 1000 (b) 1200 (c) 800
  14. 14.Best estimate of 21 × 49? (a) 10000 (b) 100 (c) 1000
  15. 15.Best estimate of 18 × 73? (a) 1400 (b) 14000 (c) 140
  16. 16.Best estimate of 78 × 61? (a) 4800 (b) 480 (c) 48000
  17. 17.Best estimate of 270 + 793? (a) 1300 (b) 1100 (c) 900
  18. 18.Best estimate of 82 × 53? (a) 4000 (b) 40000 (c) 400
  19. 19.Best estimate of 28 × 66? (a) 21000 (b) 210 (c) 2100
  20. 20.Best estimate of 671 + 407? (a) 900 (b) 1100 (c) 1300
  21. 21.Best estimate of 96 × 77? (a) 800 (b) 80000 (c) 8000
  22. 22.Best estimate of 200 + 279? (a) 500 (b) 300 (c) 700
  23. 23.Best estimate of 29 × 39? (a) 1200 (b) 12000 (c) 120
  24. 24.Best estimate of 774 + 373? (a) 1200 (b) 1400 (c) 1000
  25. 25.Best estimate of 242 + 133? (a) 500 (b) 300 (c) 100
  26. 26.Best estimate of 307 + 558? (a) 1100 (b) 700 (c) 900
  27. 27.Best estimate of 225 + 582? (a) 800 (b) 1000 (c) 600
  28. 28.Best estimate of 73 × 52? (a) 3500 (b) 35000 (c) 350
  29. 29.Best estimate of 36 × 31? (a) 12000 (b) 1200 (c) 120
  30. 30.Best estimate of 31 × 88? (a) 270 (b) 2700 (c) 27000
  31. 31.Best estimate of 26 × 46? (a) 15000 (b) 1500 (c) 150
  32. 32.Best estimate of 412 + 725? (a) 900 (b) 1300 (c) 1100
  33. 33.Best estimate of 473 + 869? (a) 1200 (b) 1600 (c) 1400
  34. 34.Best estimate of 173 + 172? (a) 600 (b) 200 (c) 400
  35. 35.Best estimate of 363 + 796? (a) 1200 (b) 1400 (c) 1000
  36. 36.Best estimate of 83 × 81? (a) 64000 (b) 640 (c) 6400
  37. 37.Best estimate of 12 × 36? (a) 40 (b) 400 (c) 4000
  38. 38.Best estimate of 593 + 143? (a) 900 (b) 500 (c) 700
  39. 39.Best estimate of 43 × 87? (a) 36000 (b) 360 (c) 3600
  40. 40.Best estimate of 226 + 204? (a) 600 (b) 400 (c) 200

Answer key

  1. 1000
  2. 800
  3. 1800
  4. 700
  5. 1600
  6. 1200
  7. 600
  8. 1600
  9. 1800
  10. 5400
  11. 3000
  12. 1600
  13. 1000
  14. 1000
  15. 1400
  16. 4800
  17. 1100
  18. 4000
  19. 2100
  20. 1100
  21. 8000
  22. 500
  23. 1200
  24. 1200
  25. 300
  26. 900
  27. 800
  28. 3500
  29. 1200
  30. 2700
  31. 1500
  32. 1100
  33. 1400
  34. 400
  35. 1200
  36. 6400
  37. 400
  38. 700
  39. 3600
  40. 400

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