← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 520 · 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 33 × 58? (a) 1800 (b) 180 (c) 18000
  2. 2.Best estimate of 61 × 48? (a) 30000 (b) 300 (c) 3000
  3. 3.Best estimate of 173 + 419? (a) 600 (b) 400 (c) 800
  4. 4.Best estimate of 299 + 614? (a) 900 (b) 700 (c) 1100
  5. 5.Best estimate of 53 × 64? (a) 30000 (b) 300 (c) 3000
  6. 6.Best estimate of 298 + 284? (a) 600 (b) 800 (c) 400
  7. 7.Best estimate of 541 + 564? (a) 900 (b) 1300 (c) 1100
  8. 8.Best estimate of 64 × 77? (a) 48000 (b) 480 (c) 4800
  9. 9.Best estimate of 167 + 346? (a) 500 (b) 300 (c) 700
  10. 10.Best estimate of 70 × 88? (a) 6300 (b) 63000 (c) 630
  11. 11.Best estimate of 810 + 697? (a) 1300 (b) 1500 (c) 1700
  12. 12.Best estimate of 28 × 22? (a) 60 (b) 6000 (c) 600
  13. 13.Best estimate of 20 × 71? (a) 140 (b) 14000 (c) 1400
  14. 14.Best estimate of 785 + 863? (a) 1500 (b) 1900 (c) 1700
  15. 15.Best estimate of 412 + 522? (a) 700 (b) 900 (c) 1100
  16. 16.Best estimate of 43 × 36? (a) 160 (b) 16000 (c) 1600
  17. 17.Best estimate of 483 + 270? (a) 800 (b) 600 (c) 1000
  18. 18.Best estimate of 64 × 70? (a) 42000 (b) 4200 (c) 420
  19. 19.Best estimate of 613 + 263? (a) 700 (b) 1100 (c) 900
  20. 20.Best estimate of 181 + 724? (a) 1100 (b) 900 (c) 700
  21. 21.Best estimate of 64 × 68? (a) 42000 (b) 4200 (c) 420
  22. 22.Best estimate of 344 + 420? (a) 900 (b) 500 (c) 700
  23. 23.Best estimate of 79 × 89? (a) 7200 (b) 720 (c) 72000
  24. 24.Best estimate of 16 × 49? (a) 10000 (b) 1000 (c) 100
  25. 25.Best estimate of 274 + 880? (a) 1200 (b) 1400 (c) 1000
  26. 26.Best estimate of 91 × 26? (a) 2700 (b) 270 (c) 27000
  27. 27.Best estimate of 63 × 72? (a) 42000 (b) 420 (c) 4200
  28. 28.Best estimate of 90 × 29? (a) 270 (b) 27000 (c) 2700
  29. 29.Best estimate of 783 + 134? (a) 900 (b) 1100 (c) 700
  30. 30.Best estimate of 14 × 82? (a) 80 (b) 8000 (c) 800
  31. 31.Best estimate of 80 × 84? (a) 64000 (b) 6400 (c) 640
  32. 32.Best estimate of 76 × 24? (a) 1600 (b) 16000 (c) 160
  33. 33.Best estimate of 183 + 500? (a) 700 (b) 500 (c) 900
  34. 34.Best estimate of 747 + 432? (a) 900 (b) 1100 (c) 1300
  35. 35.Best estimate of 89 × 16? (a) 180 (b) 18000 (c) 1800
  36. 36.Best estimate of 20 × 51? (a) 1000 (b) 10000 (c) 100
  37. 37.Best estimate of 332 + 846? (a) 900 (b) 1300 (c) 1100
  38. 38.Best estimate of 72 × 40? (a) 2800 (b) 28000 (c) 280
  39. 39.Best estimate of 18 × 46? (a) 100 (b) 10000 (c) 1000
  40. 40.Best estimate of 151 + 417? (a) 800 (b) 400 (c) 600

Answer key

  1. 1800
  2. 3000
  3. 600
  4. 900
  5. 3000
  6. 600
  7. 1100
  8. 4800
  9. 500
  10. 6300
  11. 1500
  12. 600
  13. 1400
  14. 1700
  15. 900
  16. 1600
  17. 800
  18. 4200
  19. 900
  20. 900
  21. 4200
  22. 700
  23. 7200
  24. 1000
  25. 1200
  26. 2700
  27. 4200
  28. 2700
  29. 900
  30. 800
  31. 6400
  32. 1600
  33. 700
  34. 1100
  35. 1800
  36. 1000
  37. 1100
  38. 2800
  39. 1000
  40. 600

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