← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 44 · 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 257 + 160? (a) 300 (b) 500 (c) 700
  2. 2.Best estimate of 569 + 139? (a) 700 (b) 500 (c) 900
  3. 3.Best estimate of 49 × 79? (a) 400 (b) 40000 (c) 4000
  4. 4.Best estimate of 38 × 87? (a) 360 (b) 36000 (c) 3600
  5. 5.Best estimate of 31 × 44? (a) 1200 (b) 12000 (c) 120
  6. 6.Best estimate of 12 × 46? (a) 5000 (b) 500 (c) 50
  7. 7.Best estimate of 87 × 16? (a) 18000 (b) 180 (c) 1800
  8. 8.Best estimate of 30 × 66? (a) 2100 (b) 210 (c) 21000
  9. 9.Best estimate of 18 × 29? (a) 6000 (b) 60 (c) 600
  10. 10.Best estimate of 91 × 31? (a) 270 (b) 27000 (c) 2700
  11. 11.Best estimate of 135 + 739? (a) 1000 (b) 800 (c) 600
  12. 12.Best estimate of 31 × 56? (a) 18000 (b) 1800 (c) 180
  13. 13.Best estimate of 47 × 62? (a) 300 (b) 3000 (c) 30000
  14. 14.Best estimate of 88 × 68? (a) 6300 (b) 63000 (c) 630
  15. 15.Best estimate of 93 × 51? (a) 45000 (b) 450 (c) 4500
  16. 16.Best estimate of 378 + 423? (a) 600 (b) 1000 (c) 800
  17. 17.Best estimate of 342 + 485? (a) 1000 (b) 800 (c) 600
  18. 18.Best estimate of 89 × 76? (a) 720 (b) 72000 (c) 7200
  19. 19.Best estimate of 78 × 84? (a) 640 (b) 64000 (c) 6400
  20. 20.Best estimate of 63 × 66? (a) 420 (b) 4200 (c) 42000
  21. 21.Best estimate of 58 × 39? (a) 24000 (b) 240 (c) 2400
  22. 22.Best estimate of 72 × 53? (a) 350 (b) 3500 (c) 35000
  23. 23.Best estimate of 59 × 64? (a) 360 (b) 36000 (c) 3600
  24. 24.Best estimate of 258 + 214? (a) 700 (b) 500 (c) 300
  25. 25.Best estimate of 26 × 14? (a) 30 (b) 300 (c) 3000
  26. 26.Best estimate of 621 + 369? (a) 800 (b) 1000 (c) 1200
  27. 27.Best estimate of 36 × 86? (a) 36000 (b) 360 (c) 3600
  28. 28.Best estimate of 34 × 23? (a) 600 (b) 6000 (c) 60
  29. 29.Best estimate of 38 × 63? (a) 24000 (b) 2400 (c) 240
  30. 30.Best estimate of 53 × 61? (a) 30000 (b) 300 (c) 3000
  31. 31.Best estimate of 83 × 93? (a) 72000 (b) 7200 (c) 720
  32. 32.Best estimate of 91 × 28? (a) 2700 (b) 27000 (c) 270
  33. 33.Best estimate of 53 × 88? (a) 45000 (b) 4500 (c) 450
  34. 34.Best estimate of 71 × 79? (a) 5600 (b) 56000 (c) 560
  35. 35.Best estimate of 652 + 767? (a) 1300 (b) 1500 (c) 1700
  36. 36.Best estimate of 12 × 89? (a) 90 (b) 900 (c) 9000
  37. 37.Best estimate of 13 × 26? (a) 30 (b) 3000 (c) 300
  38. 38.Best estimate of 670 + 660? (a) 1200 (b) 1600 (c) 1400
  39. 39.Best estimate of 144 + 866? (a) 1000 (b) 800 (c) 1200
  40. 40.Best estimate of 13 × 63? (a) 600 (b) 60 (c) 6000

Answer key

  1. 500
  2. 700
  3. 4000
  4. 3600
  5. 1200
  6. 500
  7. 1800
  8. 2100
  9. 600
  10. 2700
  11. 800
  12. 1800
  13. 3000
  14. 6300
  15. 4500
  16. 800
  17. 800
  18. 7200
  19. 6400
  20. 4200
  21. 2400
  22. 3500
  23. 3600
  24. 500
  25. 300
  26. 1000
  27. 3600
  28. 600
  29. 2400
  30. 3000
  31. 7200
  32. 2700
  33. 4500
  34. 5600
  35. 1500
  36. 900
  37. 300
  38. 1400
  39. 1000
  40. 600

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