← 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 97 · 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 + … + 72 =
  2. 2.1 + 2 + 3 + … + 69 =
  3. 3.1 + 2 + 3 + … + 100 =
  4. 4.1 + 2 + 3 + … + 54 =
  5. 5.1 + 3 + 5 + … + 43 =
  6. 6.1 + 2 + 3 + … + 89 =
  7. 7.1 + 2 + 3 + … + 32 =
  8. 8.1 + 3 + 5 + … + 47 =
  9. 9.1 + 3 + 5 + … + 35 =
  10. 10.1 + 3 + 5 + … + 41 =
  11. 11.1 + 3 + 5 + … + 13 =
  12. 12.1 + 3 + 5 + … + 29 =
  13. 13.1 + 2 + 3 + … + 39 =
  14. 14.1 + 3 + 5 + … + 19 =
  15. 15.1 + 3 + 5 + … + 11 =
  16. 16.1 + 2 + 3 + … + 92 =
  17. 17.1 + 2 + 3 + … + 86 =
  18. 18.1 + 2 + 3 + … + 13 =
  19. 19.1 + 2 + 3 + … + 75 =
  20. 20.1 + 2 + 3 + … + 21 =
  21. 21.1 + 3 + 5 + … + 23 =
  22. 22.1 + 2 + 3 + … + 57 =
  23. 23.1 + 3 + 5 + … + 39 =
  24. 24.1 + 2 + 3 + … + 11 =
  25. 25.1 + 2 + 3 + … + 14 =
  26. 26.1 + 3 + 5 + … + 9 =
  27. 27.1 + 2 + 3 + … + 47 =
  28. 28.1 + 3 + 5 + … + 25 =
  29. 29.1 + 2 + 3 + … + 84 =
  30. 30.1 + 2 + 3 + … + 56 =
  31. 31.1 + 2 + 3 + … + 76 =
  32. 32.1 + 3 + 5 + … + 17 =
  33. 33.1 + 2 + 3 + … + 67 =
  34. 34.1 + 2 + 3 + … + 64 =
  35. 35.1 + 2 + 3 + … + 74 =
  36. 36.1 + 3 + 5 + … + 21 =
  37. 37.1 + 2 + 3 + … + 99 =
  38. 38.1 + 2 + 3 + … + 43 =
  39. 39.1 + 3 + 5 + … + 31 =
  40. 40.1 + 2 + 3 + … + 30 =

Answer key

  1. 2628
  2. 2415
  3. 5050
  4. 1485
  5. 484
  6. 4005
  7. 528
  8. 576
  9. 324
  10. 441
  11. 49
  12. 225
  13. 780
  14. 100
  15. 36
  16. 4278
  17. 3741
  18. 91
  19. 2850
  20. 231
  21. 144
  22. 1653
  23. 400
  24. 66
  25. 105
  26. 25
  27. 1128
  28. 169
  29. 3570
  30. 1596
  31. 2926
  32. 81
  33. 2278
  34. 2080
  35. 2775
  36. 121
  37. 4950
  38. 946
  39. 256
  40. 465

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