← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 829 · 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 31 × 20? (a) 60 (b) 600 (c) 6000
  2. 2.Best estimate of 27 × 71? (a) 210 (b) 2100 (c) 21000
  3. 3.Best estimate of 728 + 814? (a) 1300 (b) 1700 (c) 1500
  4. 4.Best estimate of 330 + 545? (a) 800 (b) 600 (c) 1000
  5. 5.Best estimate of 34 × 61? (a) 1800 (b) 180 (c) 18000
  6. 6.Best estimate of 225 + 620? (a) 1000 (b) 600 (c) 800
  7. 7.Best estimate of 531 + 786? (a) 1500 (b) 1300 (c) 1100
  8. 8.Best estimate of 67 × 86? (a) 6300 (b) 63000 (c) 630
  9. 9.Best estimate of 76 × 27? (a) 24000 (b) 240 (c) 2400
  10. 10.Best estimate of 798 + 193? (a) 800 (b) 1000 (c) 1200
  11. 11.Best estimate of 21 × 44? (a) 800 (b) 8000 (c) 80
  12. 12.Best estimate of 431 + 273? (a) 900 (b) 500 (c) 700
  13. 13.Best estimate of 84 × 18? (a) 160 (b) 1600 (c) 16000
  14. 14.Best estimate of 36 × 23? (a) 8000 (b) 80 (c) 800
  15. 15.Best estimate of 59 × 78? (a) 480 (b) 4800 (c) 48000
  16. 16.Best estimate of 26 × 91? (a) 270 (b) 27000 (c) 2700
  17. 17.Best estimate of 547 + 510? (a) 800 (b) 1200 (c) 1000
  18. 18.Best estimate of 68 × 98? (a) 7000 (b) 70000 (c) 700
  19. 19.Best estimate of 84 × 29? (a) 2400 (b) 240 (c) 24000
  20. 20.Best estimate of 56 × 76? (a) 4800 (b) 480 (c) 48000
  21. 21.Best estimate of 240 + 168? (a) 600 (b) 400 (c) 200
  22. 22.Best estimate of 449 + 159? (a) 400 (b) 600 (c) 800
  23. 23.Best estimate of 79 × 24? (a) 1600 (b) 16000 (c) 160
  24. 24.Best estimate of 36 × 16? (a) 8000 (b) 800 (c) 80
  25. 25.Best estimate of 84 × 24? (a) 1600 (b) 16000 (c) 160
  26. 26.Best estimate of 22 × 96? (a) 200 (b) 2000 (c) 20000
  27. 27.Best estimate of 410 + 476? (a) 900 (b) 700 (c) 1100
  28. 28.Best estimate of 235 + 643? (a) 600 (b) 800 (c) 1000
  29. 29.Best estimate of 96 × 27? (a) 30000 (b) 300 (c) 3000
  30. 30.Best estimate of 507 + 128? (a) 600 (b) 800 (c) 400
  31. 31.Best estimate of 97 × 87? (a) 900 (b) 9000 (c) 90000
  32. 32.Best estimate of 40 × 14? (a) 400 (b) 4000 (c) 40
  33. 33.Best estimate of 46 × 24? (a) 100 (b) 1000 (c) 10000
  34. 34.Best estimate of 49 × 49? (a) 25000 (b) 2500 (c) 250
  35. 35.Best estimate of 285 + 290? (a) 600 (b) 400 (c) 800
  36. 36.Best estimate of 489 + 513? (a) 1000 (b) 1200 (c) 800
  37. 37.Best estimate of 56 × 62? (a) 3600 (b) 36000 (c) 360
  38. 38.Best estimate of 311 + 352? (a) 900 (b) 500 (c) 700
  39. 39.Best estimate of 711 + 823? (a) 1700 (b) 1500 (c) 1300
  40. 40.Best estimate of 186 + 511? (a) 900 (b) 700 (c) 500

Answer key

  1. 600
  2. 2100
  3. 1500
  4. 800
  5. 1800
  6. 800
  7. 1300
  8. 6300
  9. 2400
  10. 1000
  11. 800
  12. 700
  13. 1600
  14. 800
  15. 4800
  16. 2700
  17. 1000
  18. 7000
  19. 2400
  20. 4800
  21. 400
  22. 600
  23. 1600
  24. 800
  25. 1600
  26. 2000
  27. 900
  28. 800
  29. 3000
  30. 600
  31. 9000
  32. 400
  33. 1000
  34. 2500
  35. 600
  36. 1000
  37. 3600
  38. 700
  39. 1500
  40. 700

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