← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 797 · 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 88 × 86? (a) 8100 (b) 81000 (c) 810
  2. 2.Best estimate of 665 + 157? (a) 1100 (b) 700 (c) 900
  3. 3.Best estimate of 196 + 416? (a) 800 (b) 600 (c) 400
  4. 4.Best estimate of 266 + 751? (a) 1300 (b) 1100 (c) 900
  5. 5.Best estimate of 62 × 66? (a) 420 (b) 4200 (c) 42000
  6. 6.Best estimate of 83 × 19? (a) 1600 (b) 16000 (c) 160
  7. 7.Best estimate of 24 × 57? (a) 1200 (b) 12000 (c) 120
  8. 8.Best estimate of 504 + 327? (a) 1000 (b) 800 (c) 600
  9. 9.Best estimate of 379 + 293? (a) 900 (b) 500 (c) 700
  10. 10.Best estimate of 215 + 745? (a) 700 (b) 900 (c) 1100
  11. 11.Best estimate of 58 × 88? (a) 540 (b) 5400 (c) 54000
  12. 12.Best estimate of 71 × 57? (a) 420 (b) 4200 (c) 42000
  13. 13.Best estimate of 96 × 50? (a) 5000 (b) 50000 (c) 500
  14. 14.Best estimate of 16 × 51? (a) 10000 (b) 100 (c) 1000
  15. 15.Best estimate of 208 + 565? (a) 1000 (b) 800 (c) 600
  16. 16.Best estimate of 566 + 845? (a) 1400 (b) 1200 (c) 1600
  17. 17.Best estimate of 16 × 28? (a) 600 (b) 6000 (c) 60
  18. 18.Best estimate of 802 + 756? (a) 1400 (b) 1800 (c) 1600
  19. 19.Best estimate of 547 + 257? (a) 600 (b) 800 (c) 1000
  20. 20.Best estimate of 52 × 87? (a) 4500 (b) 45000 (c) 450
  21. 21.Best estimate of 493 + 791? (a) 1500 (b) 1100 (c) 1300
  22. 22.Best estimate of 122 + 708? (a) 600 (b) 1000 (c) 800
  23. 23.Best estimate of 36 × 63? (a) 2400 (b) 24000 (c) 240
  24. 24.Best estimate of 131 + 833? (a) 700 (b) 1100 (c) 900
  25. 25.Best estimate of 39 × 37? (a) 1600 (b) 16000 (c) 160
  26. 26.Best estimate of 18 × 21? (a) 40 (b) 4000 (c) 400
  27. 27.Best estimate of 470 + 770? (a) 1500 (b) 1100 (c) 1300
  28. 28.Best estimate of 793 + 267? (a) 1100 (b) 900 (c) 1300
  29. 29.Best estimate of 93 × 40? (a) 3600 (b) 360 (c) 36000
  30. 30.Best estimate of 826 + 557? (a) 1600 (b) 1200 (c) 1400
  31. 31.Best estimate of 468 + 425? (a) 1100 (b) 900 (c) 700
  32. 32.Best estimate of 68 × 76? (a) 5600 (b) 560 (c) 56000
  33. 33.Best estimate of 46 × 36? (a) 200 (b) 2000 (c) 20000
  34. 34.Best estimate of 30 × 58? (a) 1800 (b) 18000 (c) 180
  35. 35.Best estimate of 50 × 47? (a) 250 (b) 2500 (c) 25000
  36. 36.Best estimate of 130 + 372? (a) 700 (b) 500 (c) 300
  37. 37.Best estimate of 761 + 391? (a) 1400 (b) 1000 (c) 1200
  38. 38.Best estimate of 46 × 66? (a) 35000 (b) 350 (c) 3500
  39. 39.Best estimate of 51 × 90? (a) 45000 (b) 4500 (c) 450
  40. 40.Best estimate of 80 × 57? (a) 48000 (b) 4800 (c) 480

Answer key

  1. 8100
  2. 900
  3. 600
  4. 1100
  5. 4200
  6. 1600
  7. 1200
  8. 800
  9. 700
  10. 900
  11. 5400
  12. 4200
  13. 5000
  14. 1000
  15. 800
  16. 1400
  17. 600
  18. 1600
  19. 800
  20. 4500
  21. 1300
  22. 800
  23. 2400
  24. 900
  25. 1600
  26. 400
  27. 1300
  28. 1100
  29. 3600
  30. 1400
  31. 900
  32. 5600
  33. 2000
  34. 1800
  35. 2500
  36. 500
  37. 1200
  38. 3500
  39. 4500
  40. 4800

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