← 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 357 · 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 + … + 37 =
  2. 2.1 + 3 + 5 + … + 41 =
  3. 3.1 + 2 + 3 + … + 72 =
  4. 4.1 + 2 + 3 + … + 54 =
  5. 5.1 + 3 + 5 + … + 21 =
  6. 6.1 + 2 + 3 + … + 49 =
  7. 7.1 + 2 + 3 + … + 9 =
  8. 8.1 + 2 + 3 + … + 23 =
  9. 9.1 + 3 + 5 + … + 9 =
  10. 10.1 + 2 + 3 + … + 26 =
  11. 11.1 + 2 + 3 + … + 92 =
  12. 12.1 + 3 + 5 + … + 19 =
  13. 13.1 + 2 + 3 + … + 74 =
  14. 14.1 + 2 + 3 + … + 73 =
  15. 15.1 + 2 + 3 + … + 85 =
  16. 16.1 + 3 + 5 + … + 45 =
  17. 17.1 + 3 + 5 + … + 47 =
  18. 18.1 + 2 + 3 + … + 12 =
  19. 19.1 + 2 + 3 + … + 29 =
  20. 20.1 + 2 + 3 + … + 80 =
  21. 21.1 + 2 + 3 + … + 64 =
  22. 22.1 + 3 + 5 + … + 11 =
  23. 23.1 + 3 + 5 + … + 25 =
  24. 24.1 + 2 + 3 + … + 52 =
  25. 25.1 + 2 + 3 + … + 55 =
  26. 26.1 + 2 + 3 + … + 10 =
  27. 27.1 + 2 + 3 + … + 6 =
  28. 28.1 + 3 + 5 + … + 43 =
  29. 29.1 + 2 + 3 + … + 30 =
  30. 30.1 + 2 + 3 + … + 97 =
  31. 31.1 + 2 + 3 + … + 51 =
  32. 32.1 + 3 + 5 + … + 15 =
  33. 33.1 + 2 + 3 + … + 59 =
  34. 34.1 + 2 + 3 + … + 19 =
  35. 35.1 + 2 + 3 + … + 62 =
  36. 36.1 + 3 + 5 + … + 29 =
  37. 37.1 + 3 + 5 + … + 49 =
  38. 38.1 + 2 + 3 + … + 41 =
  39. 39.1 + 2 + 3 + … + 44 =
  40. 40.1 + 2 + 3 + … + 98 =

Answer key

  1. 361
  2. 441
  3. 2628
  4. 1485
  5. 121
  6. 1225
  7. 45
  8. 276
  9. 25
  10. 351
  11. 4278
  12. 100
  13. 2775
  14. 2701
  15. 3655
  16. 529
  17. 576
  18. 78
  19. 435
  20. 3240
  21. 2080
  22. 36
  23. 169
  24. 1378
  25. 1540
  26. 55
  27. 21
  28. 484
  29. 465
  30. 4753
  31. 1326
  32. 64
  33. 1770
  34. 190
  35. 1953
  36. 225
  37. 625
  38. 861
  39. 990
  40. 4851

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