← 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 664 · 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 + … + 23 =
  2. 2.1 + 3 + 5 + … + 13 =
  3. 3.1 + 3 + 5 + … + 11 =
  4. 4.1 + 2 + 3 + … + 17 =
  5. 5.1 + 2 + 3 + … + 10 =
  6. 6.1 + 2 + 3 + … + 44 =
  7. 7.1 + 3 + 5 + … + 43 =
  8. 8.1 + 2 + 3 + … + 24 =
  9. 9.1 + 2 + 3 + … + 91 =
  10. 10.1 + 2 + 3 + … + 62 =
  11. 11.1 + 2 + 3 + … + 89 =
  12. 12.1 + 2 + 3 + … + 70 =
  13. 13.1 + 2 + 3 + … + 13 =
  14. 14.1 + 2 + 3 + … + 36 =
  15. 15.1 + 2 + 3 + … + 53 =
  16. 16.1 + 2 + 3 + … + 6 =
  17. 17.1 + 2 + 3 + … + 32 =
  18. 18.1 + 2 + 3 + … + 69 =
  19. 19.1 + 2 + 3 + … + 22 =
  20. 20.1 + 2 + 3 + … + 99 =
  21. 21.1 + 3 + 5 + … + 45 =
  22. 22.1 + 2 + 3 + … + 23 =
  23. 23.1 + 2 + 3 + … + 82 =
  24. 24.1 + 3 + 5 + … + 49 =
  25. 25.1 + 3 + 5 + … + 27 =
  26. 26.1 + 2 + 3 + … + 73 =
  27. 27.1 + 2 + 3 + … + 79 =
  28. 28.1 + 3 + 5 + … + 35 =
  29. 29.1 + 3 + 5 + … + 9 =
  30. 30.1 + 2 + 3 + … + 18 =
  31. 31.1 + 2 + 3 + … + 94 =
  32. 32.1 + 2 + 3 + … + 77 =
  33. 33.1 + 3 + 5 + … + 31 =
  34. 34.1 + 3 + 5 + … + 47 =
  35. 35.1 + 2 + 3 + … + 19 =
  36. 36.1 + 3 + 5 + … + 37 =
  37. 37.1 + 2 + 3 + … + 58 =
  38. 38.1 + 2 + 3 + … + 88 =
  39. 39.1 + 3 + 5 + … + 17 =
  40. 40.1 + 2 + 3 + … + 95 =

Answer key

  1. 144
  2. 49
  3. 36
  4. 153
  5. 55
  6. 990
  7. 484
  8. 300
  9. 4186
  10. 1953
  11. 4005
  12. 2485
  13. 91
  14. 666
  15. 1431
  16. 21
  17. 528
  18. 2415
  19. 253
  20. 4950
  21. 529
  22. 276
  23. 3403
  24. 625
  25. 196
  26. 2701
  27. 3160
  28. 324
  29. 25
  30. 171
  31. 4465
  32. 3003
  33. 256
  34. 576
  35. 190
  36. 361
  37. 1711
  38. 3916
  39. 81
  40. 4560

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