← 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 71 · 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 + … + 92 =
  2. 2.1 + 2 + 3 + … + 32 =
  3. 3.1 + 3 + 5 + … + 25 =
  4. 4.1 + 3 + 5 + … + 9 =
  5. 5.1 + 2 + 3 + … + 24 =
  6. 6.1 + 2 + 3 + … + 51 =
  7. 7.1 + 3 + 5 + … + 45 =
  8. 8.1 + 2 + 3 + … + 82 =
  9. 9.1 + 3 + 5 + … + 41 =
  10. 10.1 + 3 + 5 + … + 11 =
  11. 11.1 + 3 + 5 + … + 23 =
  12. 12.1 + 3 + 5 + … + 21 =
  13. 13.1 + 2 + 3 + … + 12 =
  14. 14.1 + 3 + 5 + … + 29 =
  15. 15.1 + 2 + 3 + … + 20 =
  16. 16.1 + 2 + 3 + … + 41 =
  17. 17.1 + 2 + 3 + … + 94 =
  18. 18.1 + 3 + 5 + … + 13 =
  19. 19.1 + 2 + 3 + … + 15 =
  20. 20.1 + 3 + 5 + … + 27 =
  21. 21.1 + 2 + 3 + … + 36 =
  22. 22.1 + 3 + 5 + … + 17 =
  23. 23.1 + 2 + 3 + … + 100 =
  24. 24.1 + 3 + 5 + … + 47 =
  25. 25.1 + 2 + 3 + … + 17 =
  26. 26.1 + 2 + 3 + … + 61 =
  27. 27.1 + 2 + 3 + … + 8 =
  28. 28.1 + 2 + 3 + … + 9 =
  29. 29.1 + 2 + 3 + … + 40 =
  30. 30.1 + 2 + 3 + … + 75 =
  31. 31.1 + 2 + 3 + … + 23 =
  32. 32.1 + 2 + 3 + … + 33 =
  33. 33.1 + 2 + 3 + … + 18 =
  34. 34.1 + 2 + 3 + … + 76 =
  35. 35.1 + 2 + 3 + … + 45 =
  36. 36.1 + 3 + 5 + … + 19 =
  37. 37.1 + 3 + 5 + … + 31 =
  38. 38.1 + 3 + 5 + … + 37 =
  39. 39.1 + 2 + 3 + … + 22 =
  40. 40.1 + 2 + 3 + … + 19 =

Answer key

  1. 4278
  2. 528
  3. 169
  4. 25
  5. 300
  6. 1326
  7. 529
  8. 3403
  9. 441
  10. 36
  11. 144
  12. 121
  13. 78
  14. 225
  15. 210
  16. 861
  17. 4465
  18. 49
  19. 120
  20. 196
  21. 666
  22. 81
  23. 5050
  24. 576
  25. 153
  26. 1891
  27. 36
  28. 45
  29. 820
  30. 2850
  31. 276
  32. 561
  33. 171
  34. 2926
  35. 1035
  36. 100
  37. 256
  38. 361
  39. 253
  40. 190

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