← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 775 · 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 282 + 153? (a) 500 (b) 300 (c) 700
  2. 2.Best estimate of 20 × 66? (a) 14000 (b) 1400 (c) 140
  3. 3.Best estimate of 30 × 60? (a) 180 (b) 1800 (c) 18000
  4. 4.Best estimate of 14 × 79? (a) 80 (b) 800 (c) 8000
  5. 5.Best estimate of 26 × 46? (a) 1500 (b) 15000 (c) 150
  6. 6.Best estimate of 712 + 429? (a) 1100 (b) 1300 (c) 900
  7. 7.Best estimate of 31 × 34? (a) 900 (b) 90 (c) 9000
  8. 8.Best estimate of 458 + 374? (a) 700 (b) 900 (c) 1100
  9. 9.Best estimate of 862 + 340? (a) 1200 (b) 1400 (c) 1000
  10. 10.Best estimate of 71 × 16? (a) 140 (b) 14000 (c) 1400
  11. 11.Best estimate of 880 + 551? (a) 1500 (b) 1700 (c) 1300
  12. 12.Best estimate of 275 + 543? (a) 800 (b) 1000 (c) 600
  13. 13.Best estimate of 860 + 640? (a) 1500 (b) 1300 (c) 1700
  14. 14.Best estimate of 278 + 308? (a) 400 (b) 600 (c) 800
  15. 15.Best estimate of 26 × 16? (a) 600 (b) 60 (c) 6000
  16. 16.Best estimate of 380 + 160? (a) 800 (b) 400 (c) 600
  17. 17.Best estimate of 50 × 53? (a) 25000 (b) 250 (c) 2500
  18. 18.Best estimate of 746 + 849? (a) 1500 (b) 1700 (c) 1300
  19. 19.Best estimate of 88 × 47? (a) 45000 (b) 4500 (c) 450
  20. 20.Best estimate of 313 + 342? (a) 800 (b) 600 (c) 400
  21. 21.Best estimate of 272 + 457? (a) 1000 (b) 600 (c) 800
  22. 22.Best estimate of 66 × 72? (a) 490 (b) 49000 (c) 4900
  23. 23.Best estimate of 42 × 24? (a) 800 (b) 8000 (c) 80
  24. 24.Best estimate of 300 + 485? (a) 1000 (b) 600 (c) 800
  25. 25.Best estimate of 13 × 64? (a) 6000 (b) 60 (c) 600
  26. 26.Best estimate of 78 × 40? (a) 3200 (b) 320 (c) 32000
  27. 27.Best estimate of 154 + 872? (a) 1100 (b) 1300 (c) 900
  28. 28.Best estimate of 775 + 685? (a) 1500 (b) 1700 (c) 1300
  29. 29.Best estimate of 89 × 23? (a) 180 (b) 18000 (c) 1800
  30. 30.Best estimate of 383 + 684? (a) 1300 (b) 900 (c) 1100
  31. 31.Best estimate of 419 + 489? (a) 900 (b) 700 (c) 1100
  32. 32.Best estimate of 707 + 763? (a) 1500 (b) 1300 (c) 1700
  33. 33.Best estimate of 602 + 756? (a) 1200 (b) 1400 (c) 1600
  34. 34.Best estimate of 822 + 684? (a) 1500 (b) 1700 (c) 1300
  35. 35.Best estimate of 391 + 135? (a) 700 (b) 300 (c) 500
  36. 36.Best estimate of 14 × 26? (a) 300 (b) 30 (c) 3000
  37. 37.Best estimate of 120 + 369? (a) 500 (b) 300 (c) 700
  38. 38.Best estimate of 834 + 721? (a) 1300 (b) 1500 (c) 1700
  39. 39.Best estimate of 183 + 578? (a) 800 (b) 1000 (c) 600
  40. 40.Best estimate of 31 × 41? (a) 12000 (b) 120 (c) 1200

Answer key

  1. 500
  2. 1400
  3. 1800
  4. 800
  5. 1500
  6. 1100
  7. 900
  8. 900
  9. 1200
  10. 1400
  11. 1500
  12. 800
  13. 1500
  14. 600
  15. 600
  16. 600
  17. 2500
  18. 1500
  19. 4500
  20. 600
  21. 800
  22. 4900
  23. 800
  24. 800
  25. 600
  26. 3200
  27. 1100
  28. 1500
  29. 1800
  30. 1100
  31. 900
  32. 1500
  33. 1400
  34. 1500
  35. 500
  36. 300
  37. 500
  38. 1500
  39. 800
  40. 1200

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