← 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 747 · 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 + 2 + 3 + … + 49 =
  2. 2.1 + 2 + 3 + … + 96 =
  3. 3.1 + 2 + 3 + … + 12 =
  4. 4.1 + 2 + 3 + … + 79 =
  5. 5.1 + 2 + 3 + … + 11 =
  6. 6.1 + 2 + 3 + … + 83 =
  7. 7.1 + 3 + 5 + … + 47 =
  8. 8.1 + 2 + 3 + … + 29 =
  9. 9.1 + 2 + 3 + … + 7 =
  10. 10.1 + 2 + 3 + … + 92 =
  11. 11.1 + 2 + 3 + … + 40 =
  12. 12.1 + 2 + 3 + … + 98 =
  13. 13.1 + 3 + 5 + … + 19 =
  14. 14.1 + 2 + 3 + … + 75 =
  15. 15.1 + 2 + 3 + … + 91 =
  16. 16.1 + 2 + 3 + … + 61 =
  17. 17.1 + 2 + 3 + … + 60 =
  18. 18.1 + 2 + 3 + … + 42 =
  19. 19.1 + 2 + 3 + … + 68 =
  20. 20.1 + 3 + 5 + … + 29 =
  21. 21.1 + 3 + 5 + … + 21 =
  22. 22.1 + 3 + 5 + … + 41 =
  23. 23.1 + 2 + 3 + … + 48 =
  24. 24.1 + 3 + 5 + … + 49 =
  25. 25.1 + 2 + 3 + … + 36 =
  26. 26.1 + 2 + 3 + … + 38 =
  27. 27.1 + 2 + 3 + … + 33 =
  28. 28.1 + 3 + 5 + … + 37 =
  29. 29.1 + 2 + 3 + … + 76 =
  30. 30.1 + 3 + 5 + … + 9 =
  31. 31.1 + 3 + 5 + … + 35 =
  32. 32.1 + 2 + 3 + … + 99 =
  33. 33.1 + 3 + 5 + … + 13 =
  34. 34.1 + 2 + 3 + … + 26 =
  35. 35.1 + 2 + 3 + … + 51 =
  36. 36.1 + 2 + 3 + … + 6 =
  37. 37.1 + 2 + 3 + … + 81 =
  38. 38.1 + 2 + 3 + … + 17 =
  39. 39.1 + 2 + 3 + … + 89 =
  40. 40.1 + 2 + 3 + … + 13 =

Answer key

  1. 1225
  2. 4656
  3. 78
  4. 3160
  5. 66
  6. 3486
  7. 576
  8. 435
  9. 28
  10. 4278
  11. 820
  12. 4851
  13. 100
  14. 2850
  15. 4186
  16. 1891
  17. 1830
  18. 903
  19. 2346
  20. 225
  21. 121
  22. 441
  23. 1176
  24. 625
  25. 666
  26. 741
  27. 561
  28. 361
  29. 2926
  30. 25
  31. 324
  32. 4950
  33. 49
  34. 351
  35. 1326
  36. 21
  37. 3321
  38. 153
  39. 4005
  40. 91

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