← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 246 · 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 40 × 57? (a) 2400 (b) 24000 (c) 240
  2. 2.Best estimate of 32 × 31? (a) 90 (b) 900 (c) 9000
  3. 3.Best estimate of 729 + 491? (a) 1400 (b) 1200 (c) 1000
  4. 4.Best estimate of 19 × 49? (a) 100 (b) 1000 (c) 10000
  5. 5.Best estimate of 852 + 590? (a) 1300 (b) 1700 (c) 1500
  6. 6.Best estimate of 658 + 494? (a) 1400 (b) 1000 (c) 1200
  7. 7.Best estimate of 278 + 839? (a) 900 (b) 1300 (c) 1100
  8. 8.Best estimate of 679 + 234? (a) 1100 (b) 900 (c) 700
  9. 9.Best estimate of 643 + 683? (a) 1300 (b) 1500 (c) 1100
  10. 10.Best estimate of 527 + 295? (a) 800 (b) 600 (c) 1000
  11. 11.Best estimate of 320 + 435? (a) 500 (b) 900 (c) 700
  12. 12.Best estimate of 710 + 877? (a) 1600 (b) 1400 (c) 1800
  13. 13.Best estimate of 20 × 48? (a) 1000 (b) 100 (c) 10000
  14. 14.Best estimate of 30 × 26? (a) 9000 (b) 900 (c) 90
  15. 15.Best estimate of 124 + 546? (a) 600 (b) 400 (c) 800
  16. 16.Best estimate of 56 × 79? (a) 48000 (b) 4800 (c) 480
  17. 17.Best estimate of 443 + 239? (a) 400 (b) 600 (c) 800
  18. 18.Best estimate of 767 + 813? (a) 1600 (b) 1800 (c) 1400
  19. 19.Best estimate of 49 × 76? (a) 4000 (b) 40000 (c) 400
  20. 20.Best estimate of 302 + 716? (a) 1200 (b) 800 (c) 1000
  21. 21.Best estimate of 590 + 232? (a) 800 (b) 1000 (c) 600
  22. 22.Best estimate of 145 + 531? (a) 600 (b) 800 (c) 400
  23. 23.Best estimate of 60 × 90? (a) 540 (b) 5400 (c) 54000
  24. 24.Best estimate of 39 × 97? (a) 40000 (b) 4000 (c) 400
  25. 25.Best estimate of 42 × 47? (a) 2000 (b) 200 (c) 20000
  26. 26.Best estimate of 572 + 643? (a) 1400 (b) 1200 (c) 1000
  27. 27.Best estimate of 30 × 41? (a) 1200 (b) 12000 (c) 120
  28. 28.Best estimate of 12 × 14? (a) 100 (b) 1000 (c) 10
  29. 29.Best estimate of 772 + 301? (a) 1100 (b) 900 (c) 1300
  30. 30.Best estimate of 94 × 81? (a) 7200 (b) 72000 (c) 720
  31. 31.Best estimate of 23 × 13? (a) 20 (b) 2000 (c) 200
  32. 32.Best estimate of 651 + 572? (a) 1100 (b) 1300 (c) 1500
  33. 33.Best estimate of 26 × 82? (a) 240 (b) 24000 (c) 2400
  34. 34.Best estimate of 36 × 34? (a) 12000 (b) 1200 (c) 120
  35. 35.Best estimate of 46 × 36? (a) 20000 (b) 200 (c) 2000
  36. 36.Best estimate of 588 + 326? (a) 900 (b) 1100 (c) 700
  37. 37.Best estimate of 334 + 400? (a) 700 (b) 900 (c) 500
  38. 38.Best estimate of 394 + 220? (a) 400 (b) 800 (c) 600
  39. 39.Best estimate of 94 × 63? (a) 54000 (b) 5400 (c) 540
  40. 40.Best estimate of 653 + 388? (a) 900 (b) 1100 (c) 1300

Answer key

  1. 2400
  2. 900
  3. 1200
  4. 1000
  5. 1500
  6. 1200
  7. 1100
  8. 900
  9. 1300
  10. 800
  11. 700
  12. 1600
  13. 1000
  14. 900
  15. 600
  16. 4800
  17. 600
  18. 1600
  19. 4000
  20. 1000
  21. 800
  22. 600
  23. 5400
  24. 4000
  25. 2000
  26. 1200
  27. 1200
  28. 100
  29. 1100
  30. 7200
  31. 200
  32. 1300
  33. 2400
  34. 1200
  35. 2000
  36. 900
  37. 700
  38. 600
  39. 5400
  40. 1100

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