← Add 1 to 100 in seconds lesson New set →

Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 486 · 40 questions
TalentJR

The trick (Pairs): Pair the first and last numbers: each pair adds to n + 1. Count the pairs — or multiply n × (n + 1) and halve it. Odd numbers 1 + 3 + 5 + …: count them and multiply that count by itself.

NameDateTime takenScore ___ / 40
  1. 1.1 + 3 + 5 + … + 39 =
  2. 2.1 + 2 + 3 + … + 67 =
  3. 3.1 + 3 + 5 + … + 21 =
  4. 4.1 + 2 + 3 + … + 10 =
  5. 5.1 + 2 + 3 + … + 86 =
  6. 6.1 + 3 + 5 + … + 13 =
  7. 7.1 + 2 + 3 + … + 100 =
  8. 8.1 + 2 + 3 + … + 82 =
  9. 9.1 + 2 + 3 + … + 14 =
  10. 10.1 + 2 + 3 + … + 20 =
  11. 11.1 + 3 + 5 + … + 31 =
  12. 12.1 + 2 + 3 + … + 57 =
  13. 13.1 + 2 + 3 + … + 53 =
  14. 14.1 + 2 + 3 + … + 94 =
  15. 15.1 + 2 + 3 + … + 84 =
  16. 16.1 + 3 + 5 + … + 27 =
  17. 17.1 + 3 + 5 + … + 35 =
  18. 18.1 + 2 + 3 + … + 74 =
  19. 19.1 + 2 + 3 + … + 41 =
  20. 20.1 + 3 + 5 + … + 19 =
  21. 21.1 + 2 + 3 + … + 72 =
  22. 22.1 + 2 + 3 + … + 27 =
  23. 23.1 + 2 + 3 + … + 29 =
  24. 24.1 + 2 + 3 + … + 65 =
  25. 25.1 + 2 + 3 + … + 18 =
  26. 26.1 + 2 + 3 + … + 15 =
  27. 27.1 + 2 + 3 + … + 69 =
  28. 28.1 + 2 + 3 + … + 97 =
  29. 29.1 + 2 + 3 + … + 51 =
  30. 30.1 + 3 + 5 + … + 41 =
  31. 31.1 + 3 + 5 + … + 47 =
  32. 32.1 + 2 + 3 + … + 71 =
  33. 33.1 + 2 + 3 + … + 62 =
  34. 34.1 + 2 + 3 + … + 90 =
  35. 35.1 + 3 + 5 + … + 23 =
  36. 36.1 + 2 + 3 + … + 68 =
  37. 37.1 + 2 + 3 + … + 40 =
  38. 38.1 + 3 + 5 + … + 15 =
  39. 39.1 + 2 + 3 + … + 92 =
  40. 40.1 + 3 + 5 + … + 43 =

Answer key

  1. 400
  2. 2278
  3. 121
  4. 55
  5. 3741
  6. 49
  7. 5050
  8. 3403
  9. 105
  10. 210
  11. 256
  12. 1653
  13. 1431
  14. 4465
  15. 3570
  16. 196
  17. 324
  18. 2775
  19. 861
  20. 100
  21. 2628
  22. 378
  23. 435
  24. 2145
  25. 171
  26. 120
  27. 2415
  28. 4753
  29. 1326
  30. 441
  31. 576
  32. 2556
  33. 1953
  34. 4095
  35. 144
  36. 2346
  37. 820
  38. 64
  39. 4278
  40. 484

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