← 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 339 · 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 + … + 33 =
  2. 2.1 + 3 + 5 + … + 29 =
  3. 3.1 + 2 + 3 + … + 42 =
  4. 4.1 + 3 + 5 + … + 35 =
  5. 5.1 + 2 + 3 + … + 69 =
  6. 6.1 + 2 + 3 + … + 54 =
  7. 7.1 + 2 + 3 + … + 93 =
  8. 8.1 + 2 + 3 + … + 53 =
  9. 9.1 + 2 + 3 + … + 94 =
  10. 10.1 + 2 + 3 + … + 27 =
  11. 11.1 + 2 + 3 + … + 59 =
  12. 12.1 + 2 + 3 + … + 34 =
  13. 13.1 + 2 + 3 + … + 67 =
  14. 14.1 + 2 + 3 + … + 72 =
  15. 15.1 + 3 + 5 + … + 21 =
  16. 16.1 + 2 + 3 + … + 18 =
  17. 17.1 + 2 + 3 + … + 21 =
  18. 18.1 + 2 + 3 + … + 66 =
  19. 19.1 + 2 + 3 + … + 57 =
  20. 20.1 + 3 + 5 + … + 27 =
  21. 21.1 + 2 + 3 + … + 52 =
  22. 22.1 + 2 + 3 + … + 22 =
  23. 23.1 + 3 + 5 + … + 41 =
  24. 24.1 + 2 + 3 + … + 49 =
  25. 25.1 + 2 + 3 + … + 76 =
  26. 26.1 + 2 + 3 + … + 23 =
  27. 27.1 + 2 + 3 + … + 97 =
  28. 28.1 + 2 + 3 + … + 74 =
  29. 29.1 + 3 + 5 + … + 17 =
  30. 30.1 + 2 + 3 + … + 13 =
  31. 31.1 + 3 + 5 + … + 19 =
  32. 32.1 + 2 + 3 + … + 10 =
  33. 33.1 + 2 + 3 + … + 51 =
  34. 34.1 + 2 + 3 + … + 25 =
  35. 35.1 + 2 + 3 + … + 15 =
  36. 36.1 + 2 + 3 + … + 56 =
  37. 37.1 + 2 + 3 + … + 83 =
  38. 38.1 + 3 + 5 + … + 43 =
  39. 39.1 + 2 + 3 + … + 61 =
  40. 40.1 + 2 + 3 + … + 98 =

Answer key

  1. 289
  2. 225
  3. 903
  4. 324
  5. 2415
  6. 1485
  7. 4371
  8. 1431
  9. 4465
  10. 378
  11. 1770
  12. 595
  13. 2278
  14. 2628
  15. 121
  16. 171
  17. 231
  18. 2211
  19. 1653
  20. 196
  21. 1378
  22. 253
  23. 441
  24. 1225
  25. 2926
  26. 276
  27. 4753
  28. 2775
  29. 81
  30. 91
  31. 100
  32. 55
  33. 1326
  34. 325
  35. 120
  36. 1596
  37. 3486
  38. 484
  39. 1891
  40. 4851

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