← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 690 · 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 421 + 621? (a) 800 (b) 1000 (c) 1200
  2. 2.Best estimate of 546 + 205? (a) 500 (b) 900 (c) 700
  3. 3.Best estimate of 755 + 638? (a) 1600 (b) 1200 (c) 1400
  4. 4.Best estimate of 27 × 23? (a) 60 (b) 600 (c) 6000
  5. 5.Best estimate of 40 × 32? (a) 120 (b) 12000 (c) 1200
  6. 6.Best estimate of 303 + 675? (a) 1000 (b) 1200 (c) 800
  7. 7.Best estimate of 36 × 48? (a) 20000 (b) 200 (c) 2000
  8. 8.Best estimate of 548 + 500? (a) 1200 (b) 1000 (c) 800
  9. 9.Best estimate of 18 × 62? (a) 1200 (b) 12000 (c) 120
  10. 10.Best estimate of 21 × 76? (a) 160 (b) 16000 (c) 1600
  11. 11.Best estimate of 20 × 54? (a) 1000 (b) 100 (c) 10000
  12. 12.Best estimate of 444 + 399? (a) 1000 (b) 800 (c) 600
  13. 13.Best estimate of 193 + 529? (a) 900 (b) 500 (c) 700
  14. 14.Best estimate of 521 + 181? (a) 700 (b) 900 (c) 500
  15. 15.Best estimate of 326 + 251? (a) 400 (b) 600 (c) 800
  16. 16.Best estimate of 318 + 460? (a) 600 (b) 800 (c) 1000
  17. 17.Best estimate of 76 × 30? (a) 2400 (b) 240 (c) 24000
  18. 18.Best estimate of 76 × 87? (a) 72000 (b) 720 (c) 7200
  19. 19.Best estimate of 137 + 274? (a) 600 (b) 200 (c) 400
  20. 20.Best estimate of 300 + 338? (a) 800 (b) 600 (c) 400
  21. 21.Best estimate of 512 + 801? (a) 1300 (b) 1500 (c) 1100
  22. 22.Best estimate of 17 × 26? (a) 6000 (b) 600 (c) 60
  23. 23.Best estimate of 789 + 879? (a) 1700 (b) 1500 (c) 1900
  24. 24.Best estimate of 322 + 240? (a) 700 (b) 500 (c) 300
  25. 25.Best estimate of 57 × 18? (a) 12000 (b) 120 (c) 1200
  26. 26.Best estimate of 214 + 538? (a) 900 (b) 700 (c) 500
  27. 27.Best estimate of 79 × 59? (a) 4800 (b) 48000 (c) 480
  28. 28.Best estimate of 36 × 96? (a) 40000 (b) 400 (c) 4000
  29. 29.Best estimate of 47 × 96? (a) 50000 (b) 5000 (c) 500
  30. 30.Best estimate of 46 × 52? (a) 250 (b) 2500 (c) 25000
  31. 31.Best estimate of 74 × 66? (a) 49000 (b) 490 (c) 4900
  32. 32.Best estimate of 56 × 61? (a) 360 (b) 36000 (c) 3600
  33. 33.Best estimate of 873 + 419? (a) 1500 (b) 1300 (c) 1100
  34. 34.Best estimate of 144 + 825? (a) 1100 (b) 900 (c) 700
  35. 35.Best estimate of 657 + 772? (a) 1500 (b) 1300 (c) 1700
  36. 36.Best estimate of 626 + 520? (a) 1300 (b) 1100 (c) 900
  37. 37.Best estimate of 824 + 210? (a) 1200 (b) 1000 (c) 800
  38. 38.Best estimate of 26 × 20? (a) 6000 (b) 60 (c) 600
  39. 39.Best estimate of 245 + 182? (a) 600 (b) 400 (c) 200
  40. 40.Best estimate of 412 + 258? (a) 900 (b) 500 (c) 700

Answer key

  1. 1000
  2. 700
  3. 1400
  4. 600
  5. 1200
  6. 1000
  7. 2000
  8. 1000
  9. 1200
  10. 1600
  11. 1000
  12. 800
  13. 700
  14. 700
  15. 600
  16. 800
  17. 2400
  18. 7200
  19. 400
  20. 600
  21. 1300
  22. 600
  23. 1700
  24. 500
  25. 1200
  26. 700
  27. 4800
  28. 4000
  29. 5000
  30. 2500
  31. 4900
  32. 3600
  33. 1300
  34. 900
  35. 1500
  36. 1100
  37. 1000
  38. 600
  39. 400
  40. 700

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