← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 330 · 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 376 + 145? (a) 500 (b) 700 (c) 300
  2. 2.Best estimate of 310 + 146? (a) 600 (b) 400 (c) 200
  3. 3.Best estimate of 77 × 51? (a) 400 (b) 4000 (c) 40000
  4. 4.Best estimate of 76 × 23? (a) 160 (b) 16000 (c) 1600
  5. 5.Best estimate of 269 + 504? (a) 1000 (b) 800 (c) 600
  6. 6.Best estimate of 555 + 449? (a) 800 (b) 1000 (c) 1200
  7. 7.Best estimate of 67 × 34? (a) 21000 (b) 2100 (c) 210
  8. 8.Best estimate of 372 + 502? (a) 900 (b) 700 (c) 1100
  9. 9.Best estimate of 470 + 835? (a) 1500 (b) 1100 (c) 1300
  10. 10.Best estimate of 53 × 63? (a) 30000 (b) 300 (c) 3000
  11. 11.Best estimate of 84 × 60? (a) 480 (b) 48000 (c) 4800
  12. 12.Best estimate of 38 × 64? (a) 2400 (b) 24000 (c) 240
  13. 13.Best estimate of 73 × 27? (a) 21000 (b) 2100 (c) 210
  14. 14.Best estimate of 84 × 30? (a) 2400 (b) 24000 (c) 240
  15. 15.Best estimate of 36 × 69? (a) 28000 (b) 2800 (c) 280
  16. 16.Best estimate of 505 + 338? (a) 600 (b) 1000 (c) 800
  17. 17.Best estimate of 739 + 157? (a) 1100 (b) 700 (c) 900
  18. 18.Best estimate of 14 × 47? (a) 5000 (b) 500 (c) 50
  19. 19.Best estimate of 847 + 474? (a) 1300 (b) 1100 (c) 1500
  20. 20.Best estimate of 128 + 176? (a) 500 (b) 100 (c) 300
  21. 21.Best estimate of 515 + 207? (a) 500 (b) 700 (c) 900
  22. 22.Best estimate of 96 × 26? (a) 300 (b) 30000 (c) 3000
  23. 23.Best estimate of 96 × 97? (a) 100000 (b) 1000 (c) 10000
  24. 24.Best estimate of 189 + 861? (a) 1100 (b) 1300 (c) 900
  25. 25.Best estimate of 159 + 281? (a) 500 (b) 300 (c) 700
  26. 26.Best estimate of 30 × 16? (a) 6000 (b) 60 (c) 600
  27. 27.Best estimate of 234 + 487? (a) 700 (b) 500 (c) 900
  28. 28.Best estimate of 582 + 878? (a) 1500 (b) 1300 (c) 1700
  29. 29.Best estimate of 84 × 41? (a) 3200 (b) 320 (c) 32000
  30. 30.Best estimate of 209 + 454? (a) 500 (b) 900 (c) 700
  31. 31.Best estimate of 61 × 79? (a) 4800 (b) 48000 (c) 480
  32. 32.Best estimate of 16 × 70? (a) 14000 (b) 1400 (c) 140
  33. 33.Best estimate of 39 × 33? (a) 120 (b) 1200 (c) 12000
  34. 34.Best estimate of 631 + 148? (a) 500 (b) 700 (c) 900
  35. 35.Best estimate of 667 + 782? (a) 1700 (b) 1300 (c) 1500
  36. 36.Best estimate of 748 + 126? (a) 1000 (b) 600 (c) 800
  37. 37.Best estimate of 425 + 735? (a) 900 (b) 1300 (c) 1100
  38. 38.Best estimate of 50 × 82? (a) 4000 (b) 40000 (c) 400
  39. 39.Best estimate of 88 × 78? (a) 72000 (b) 7200 (c) 720
  40. 40.Best estimate of 28 × 62? (a) 1800 (b) 180 (c) 18000

Answer key

  1. 500
  2. 400
  3. 4000
  4. 1600
  5. 800
  6. 1000
  7. 2100
  8. 900
  9. 1300
  10. 3000
  11. 4800
  12. 2400
  13. 2100
  14. 2400
  15. 2800
  16. 800
  17. 900
  18. 500
  19. 1300
  20. 300
  21. 700
  22. 3000
  23. 10000
  24. 1100
  25. 500
  26. 600
  27. 700
  28. 1500
  29. 3200
  30. 700
  31. 4800
  32. 1400
  33. 1200
  34. 700
  35. 1500
  36. 800
  37. 1100
  38. 4000
  39. 7200
  40. 1800

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