← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 22 · 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 288 + 285? (a) 800 (b) 600 (c) 400
  2. 2.Best estimate of 74 × 83? (a) 5600 (b) 56000 (c) 560
  3. 3.Best estimate of 47 × 29? (a) 1500 (b) 150 (c) 15000
  4. 4.Best estimate of 93 × 88? (a) 810 (b) 81000 (c) 8100
  5. 5.Best estimate of 502 + 326? (a) 600 (b) 1000 (c) 800
  6. 6.Best estimate of 91 × 12? (a) 900 (b) 90 (c) 9000
  7. 7.Best estimate of 42 × 57? (a) 240 (b) 2400 (c) 24000
  8. 8.Best estimate of 175 + 425? (a) 600 (b) 400 (c) 800
  9. 9.Best estimate of 732 + 261? (a) 1000 (b) 800 (c) 1200
  10. 10.Best estimate of 48 × 63? (a) 3000 (b) 30000 (c) 300
  11. 11.Best estimate of 28 × 34? (a) 90 (b) 9000 (c) 900
  12. 12.Best estimate of 44 × 96? (a) 4000 (b) 40000 (c) 400
  13. 13.Best estimate of 145 + 432? (a) 700 (b) 300 (c) 500
  14. 14.Best estimate of 841 + 821? (a) 1800 (b) 1400 (c) 1600
  15. 15.Best estimate of 315 + 361? (a) 900 (b) 700 (c) 500
  16. 16.Best estimate of 720 + 553? (a) 1300 (b) 1100 (c) 1500
  17. 17.Best estimate of 46 × 90? (a) 45000 (b) 450 (c) 4500
  18. 18.Best estimate of 642 + 626? (a) 1400 (b) 1000 (c) 1200
  19. 19.Best estimate of 37 × 86? (a) 36000 (b) 360 (c) 3600
  20. 20.Best estimate of 88 × 33? (a) 2700 (b) 27000 (c) 270
  21. 21.Best estimate of 38 × 94? (a) 36000 (b) 360 (c) 3600
  22. 22.Best estimate of 276 + 304? (a) 800 (b) 600 (c) 400
  23. 23.Best estimate of 647 + 619? (a) 1400 (b) 1000 (c) 1200
  24. 24.Best estimate of 50 × 36? (a) 2000 (b) 200 (c) 20000
  25. 25.Best estimate of 13 × 96? (a) 100 (b) 10000 (c) 1000
  26. 26.Best estimate of 18 × 13? (a) 200 (b) 20 (c) 2000
  27. 27.Best estimate of 41 × 82? (a) 32000 (b) 320 (c) 3200
  28. 28.Best estimate of 274 + 425? (a) 700 (b) 900 (c) 500
  29. 29.Best estimate of 16 × 31? (a) 60 (b) 600 (c) 6000
  30. 30.Best estimate of 635 + 449? (a) 1000 (b) 800 (c) 1200
  31. 31.Best estimate of 596 + 207? (a) 800 (b) 1000 (c) 600
  32. 32.Best estimate of 18 × 90? (a) 1800 (b) 180 (c) 18000
  33. 33.Best estimate of 82 × 98? (a) 8000 (b) 80000 (c) 800
  34. 34.Best estimate of 48 × 48? (a) 25000 (b) 2500 (c) 250
  35. 35.Best estimate of 49 × 13? (a) 500 (b) 5000 (c) 50
  36. 36.Best estimate of 429 + 601? (a) 800 (b) 1000 (c) 1200
  37. 37.Best estimate of 61 × 27? (a) 1800 (b) 180 (c) 18000
  38. 38.Best estimate of 634 + 292? (a) 900 (b) 700 (c) 1100
  39. 39.Best estimate of 43 × 90? (a) 36000 (b) 360 (c) 3600
  40. 40.Best estimate of 594 + 223? (a) 800 (b) 1000 (c) 600

Answer key

  1. 600
  2. 5600
  3. 1500
  4. 8100
  5. 800
  6. 900
  7. 2400
  8. 600
  9. 1000
  10. 3000
  11. 900
  12. 4000
  13. 500
  14. 1600
  15. 700
  16. 1300
  17. 4500
  18. 1200
  19. 3600
  20. 2700
  21. 3600
  22. 600
  23. 1200
  24. 2000
  25. 1000
  26. 200
  27. 3200
  28. 700
  29. 600
  30. 1000
  31. 800
  32. 1800
  33. 8000
  34. 2500
  35. 500
  36. 1000
  37. 1800
  38. 900
  39. 3600
  40. 800

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