← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 623 · 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 20 × 62? (a) 120 (b) 1200 (c) 12000
  2. 2.Best estimate of 421 + 131? (a) 700 (b) 500 (c) 300
  3. 3.Best estimate of 143 + 279? (a) 600 (b) 200 (c) 400
  4. 4.Best estimate of 23 × 90? (a) 180 (b) 18000 (c) 1800
  5. 5.Best estimate of 37 × 23? (a) 800 (b) 80 (c) 8000
  6. 6.Best estimate of 29 × 38? (a) 1200 (b) 12000 (c) 120
  7. 7.Best estimate of 599 + 384? (a) 800 (b) 1000 (c) 1200
  8. 8.Best estimate of 20 × 59? (a) 120 (b) 1200 (c) 12000
  9. 9.Best estimate of 555 + 354? (a) 1200 (b) 800 (c) 1000
  10. 10.Best estimate of 80 × 81? (a) 6400 (b) 640 (c) 64000
  11. 11.Best estimate of 394 + 509? (a) 1100 (b) 900 (c) 700
  12. 12.Best estimate of 38 × 21? (a) 800 (b) 8000 (c) 80
  13. 13.Best estimate of 410 + 638? (a) 800 (b) 1200 (c) 1000
  14. 14.Best estimate of 147 + 142? (a) 400 (b) 0 (c) 200
  15. 15.Best estimate of 375 + 524? (a) 700 (b) 1100 (c) 900
  16. 16.Best estimate of 30 × 83? (a) 240 (b) 24000 (c) 2400
  17. 17.Best estimate of 58 × 93? (a) 54000 (b) 5400 (c) 540
  18. 18.Best estimate of 70 × 76? (a) 560 (b) 56000 (c) 5600
  19. 19.Best estimate of 62 × 59? (a) 36000 (b) 360 (c) 3600
  20. 20.Best estimate of 63 × 79? (a) 4800 (b) 480 (c) 48000
  21. 21.Best estimate of 682 + 313? (a) 800 (b) 1000 (c) 1200
  22. 22.Best estimate of 207 + 616? (a) 800 (b) 1000 (c) 600
  23. 23.Best estimate of 472 + 656? (a) 1400 (b) 1000 (c) 1200
  24. 24.Best estimate of 621 + 655? (a) 1500 (b) 1300 (c) 1100
  25. 25.Best estimate of 17 × 63? (a) 1200 (b) 120 (c) 12000
  26. 26.Best estimate of 20 × 63? (a) 1200 (b) 12000 (c) 120
  27. 27.Best estimate of 83 × 69? (a) 5600 (b) 56000 (c) 560
  28. 28.Best estimate of 611 + 512? (a) 1300 (b) 900 (c) 1100
  29. 29.Best estimate of 43 × 80? (a) 3200 (b) 32000 (c) 320
  30. 30.Best estimate of 792 + 758? (a) 1600 (b) 1800 (c) 1400
  31. 31.Best estimate of 234 + 563? (a) 600 (b) 800 (c) 1000
  32. 32.Best estimate of 602 + 509? (a) 1300 (b) 1100 (c) 900
  33. 33.Best estimate of 80 × 92? (a) 72000 (b) 7200 (c) 720
  34. 34.Best estimate of 20 × 12? (a) 2000 (b) 200 (c) 20
  35. 35.Best estimate of 84 × 77? (a) 64000 (b) 640 (c) 6400
  36. 36.Best estimate of 128 + 137? (a) 0 (b) 400 (c) 200
  37. 37.Best estimate of 13 × 31? (a) 30 (b) 3000 (c) 300
  38. 38.Best estimate of 56 × 67? (a) 4200 (b) 42000 (c) 420
  39. 39.Best estimate of 265 + 678? (a) 1200 (b) 1000 (c) 800
  40. 40.Best estimate of 50 × 83? (a) 40000 (b) 4000 (c) 400

Answer key

  1. 1200
  2. 500
  3. 400
  4. 1800
  5. 800
  6. 1200
  7. 1000
  8. 1200
  9. 1000
  10. 6400
  11. 900
  12. 800
  13. 1000
  14. 200
  15. 900
  16. 2400
  17. 5400
  18. 5600
  19. 3600
  20. 4800
  21. 1000
  22. 800
  23. 1200
  24. 1300
  25. 1200
  26. 1200
  27. 5600
  28. 1100
  29. 3200
  30. 1600
  31. 800
  32. 1100
  33. 7200
  34. 200
  35. 6400
  36. 200
  37. 300
  38. 4200
  39. 1000
  40. 4000

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