← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 257 · 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 41 × 87? (a) 360 (b) 36000 (c) 3600
  2. 2.Best estimate of 21 × 17? (a) 4000 (b) 40 (c) 400
  3. 3.Best estimate of 872 + 445? (a) 1100 (b) 1300 (c) 1500
  4. 4.Best estimate of 98 × 87? (a) 9000 (b) 900 (c) 90000
  5. 5.Best estimate of 562 + 488? (a) 900 (b) 1300 (c) 1100
  6. 6.Best estimate of 174 + 751? (a) 1200 (b) 1000 (c) 800
  7. 7.Best estimate of 310 + 495? (a) 600 (b) 800 (c) 1000
  8. 8.Best estimate of 93 × 46? (a) 45000 (b) 4500 (c) 450
  9. 9.Best estimate of 446 + 505? (a) 1100 (b) 900 (c) 700
  10. 10.Best estimate of 26 × 62? (a) 1800 (b) 180 (c) 18000
  11. 11.Best estimate of 36 × 64? (a) 2400 (b) 24000 (c) 240
  12. 12.Best estimate of 351 + 616? (a) 1200 (b) 800 (c) 1000
  13. 13.Best estimate of 74 × 49? (a) 3500 (b) 350 (c) 35000
  14. 14.Best estimate of 81 × 17? (a) 160 (b) 16000 (c) 1600
  15. 15.Best estimate of 344 + 536? (a) 600 (b) 800 (c) 1000
  16. 16.Best estimate of 13 × 79? (a) 80 (b) 8000 (c) 800
  17. 17.Best estimate of 191 + 723? (a) 1100 (b) 900 (c) 700
  18. 18.Best estimate of 623 + 417? (a) 800 (b) 1000 (c) 1200
  19. 19.Best estimate of 36 × 16? (a) 8000 (b) 80 (c) 800
  20. 20.Best estimate of 222 + 204? (a) 200 (b) 400 (c) 600
  21. 21.Best estimate of 653 + 537? (a) 1200 (b) 1000 (c) 1400
  22. 22.Best estimate of 41 × 39? (a) 16000 (b) 160 (c) 1600
  23. 23.Best estimate of 759 + 776? (a) 1400 (b) 1800 (c) 1600
  24. 24.Best estimate of 132 + 129? (a) 400 (b) 200 (c) 0
  25. 25.Best estimate of 46 × 28? (a) 15000 (b) 1500 (c) 150
  26. 26.Best estimate of 73 × 48? (a) 3500 (b) 350 (c) 35000
  27. 27.Best estimate of 47 × 66? (a) 3500 (b) 350 (c) 35000
  28. 28.Best estimate of 390 + 700? (a) 900 (b) 1100 (c) 1300
  29. 29.Best estimate of 84 × 74? (a) 56000 (b) 560 (c) 5600
  30. 30.Best estimate of 520 + 366? (a) 700 (b) 900 (c) 1100
  31. 31.Best estimate of 61 × 48? (a) 30000 (b) 300 (c) 3000
  32. 32.Best estimate of 31 × 28? (a) 9000 (b) 900 (c) 90
  33. 33.Best estimate of 78 × 84? (a) 64000 (b) 640 (c) 6400
  34. 34.Best estimate of 722 + 321? (a) 1200 (b) 800 (c) 1000
  35. 35.Best estimate of 479 + 183? (a) 900 (b) 500 (c) 700
  36. 36.Best estimate of 74 × 94? (a) 6300 (b) 63000 (c) 630
  37. 37.Best estimate of 439 + 404? (a) 800 (b) 1000 (c) 600
  38. 38.Best estimate of 379 + 334? (a) 700 (b) 900 (c) 500
  39. 39.Best estimate of 41 × 56? (a) 2400 (b) 24000 (c) 240
  40. 40.Best estimate of 393 + 225? (a) 800 (b) 600 (c) 400

Answer key

  1. 3600
  2. 400
  3. 1300
  4. 9000
  5. 1100
  6. 1000
  7. 800
  8. 4500
  9. 900
  10. 1800
  11. 2400
  12. 1000
  13. 3500
  14. 1600
  15. 800
  16. 800
  17. 900
  18. 1000
  19. 800
  20. 400
  21. 1200
  22. 1600
  23. 1600
  24. 200
  25. 1500
  26. 3500
  27. 3500
  28. 1100
  29. 5600
  30. 900
  31. 3000
  32. 900
  33. 6400
  34. 1000
  35. 700
  36. 6300
  37. 800
  38. 700
  39. 2400
  40. 600

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