← 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 892 · 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 + … + 49 =
  2. 2.1 + 2 + 3 + … + 65 =
  3. 3.1 + 3 + 5 + … + 9 =
  4. 4.1 + 2 + 3 + … + 96 =
  5. 5.1 + 3 + 5 + … + 23 =
  6. 6.1 + 3 + 5 + … + 27 =
  7. 7.1 + 2 + 3 + … + 69 =
  8. 8.1 + 2 + 3 + … + 51 =
  9. 9.1 + 2 + 3 + … + 33 =
  10. 10.1 + 3 + 5 + … + 17 =
  11. 11.1 + 2 + 3 + … + 94 =
  12. 12.1 + 2 + 3 + … + 24 =
  13. 13.1 + 2 + 3 + … + 76 =
  14. 14.1 + 2 + 3 + … + 67 =
  15. 15.1 + 2 + 3 + … + 15 =
  16. 16.1 + 2 + 3 + … + 23 =
  17. 17.1 + 2 + 3 + … + 52 =
  18. 18.1 + 2 + 3 + … + 71 =
  19. 19.1 + 2 + 3 + … + 9 =
  20. 20.1 + 2 + 3 + … + 16 =
  21. 21.1 + 2 + 3 + … + 97 =
  22. 22.1 + 2 + 3 + … + 44 =
  23. 23.1 + 3 + 5 + … + 39 =
  24. 24.1 + 2 + 3 + … + 90 =
  25. 25.1 + 2 + 3 + … + 32 =
  26. 26.1 + 2 + 3 + … + 43 =
  27. 27.1 + 2 + 3 + … + 99 =
  28. 28.1 + 2 + 3 + … + 25 =
  29. 29.1 + 2 + 3 + … + 36 =
  30. 30.1 + 3 + 5 + … + 33 =
  31. 31.1 + 2 + 3 + … + 55 =
  32. 32.1 + 2 + 3 + … + 40 =
  33. 33.1 + 3 + 5 + … + 25 =
  34. 34.1 + 3 + 5 + … + 21 =
  35. 35.1 + 2 + 3 + … + 82 =
  36. 36.1 + 3 + 5 + … + 15 =
  37. 37.1 + 2 + 3 + … + 61 =
  38. 38.1 + 3 + 5 + … + 43 =
  39. 39.1 + 2 + 3 + … + 68 =
  40. 40.1 + 2 + 3 + … + 46 =

Answer key

  1. 1225
  2. 2145
  3. 25
  4. 4656
  5. 144
  6. 196
  7. 2415
  8. 1326
  9. 561
  10. 81
  11. 4465
  12. 300
  13. 2926
  14. 2278
  15. 120
  16. 276
  17. 1378
  18. 2556
  19. 45
  20. 136
  21. 4753
  22. 990
  23. 400
  24. 4095
  25. 528
  26. 946
  27. 4950
  28. 325
  29. 666
  30. 289
  31. 1540
  32. 820
  33. 169
  34. 121
  35. 3403
  36. 64
  37. 1891
  38. 484
  39. 2346
  40. 1081

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