← 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 886 · 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 + 2 + 3 + … + 7 =
  3. 3.1 + 2 + 3 + … + 91 =
  4. 4.1 + 2 + 3 + … + 8 =
  5. 5.1 + 2 + 3 + … + 20 =
  6. 6.1 + 2 + 3 + … + 46 =
  7. 7.1 + 2 + 3 + … + 24 =
  8. 8.1 + 2 + 3 + … + 21 =
  9. 9.1 + 3 + 5 + … + 19 =
  10. 10.1 + 2 + 3 + … + 60 =
  11. 11.1 + 2 + 3 + … + 15 =
  12. 12.1 + 3 + 5 + … + 37 =
  13. 13.1 + 2 + 3 + … + 12 =
  14. 14.1 + 2 + 3 + … + 31 =
  15. 15.1 + 2 + 3 + … + 45 =
  16. 16.1 + 2 + 3 + … + 96 =
  17. 17.1 + 2 + 3 + … + 98 =
  18. 18.1 + 3 + 5 + … + 9 =
  19. 19.1 + 2 + 3 + … + 42 =
  20. 20.1 + 2 + 3 + … + 79 =
  21. 21.1 + 3 + 5 + … + 49 =
  22. 22.1 + 2 + 3 + … + 86 =
  23. 23.1 + 2 + 3 + … + 62 =
  24. 24.1 + 3 + 5 + … + 39 =
  25. 25.1 + 2 + 3 + … + 69 =
  26. 26.1 + 2 + 3 + … + 70 =
  27. 27.1 + 2 + 3 + … + 14 =
  28. 28.1 + 2 + 3 + … + 50 =
  29. 29.1 + 2 + 3 + … + 84 =
  30. 30.1 + 2 + 3 + … + 75 =
  31. 31.1 + 2 + 3 + … + 90 =
  32. 32.1 + 2 + 3 + … + 9 =
  33. 33.1 + 2 + 3 + … + 52 =
  34. 34.1 + 2 + 3 + … + 18 =
  35. 35.1 + 3 + 5 + … + 27 =
  36. 36.1 + 2 + 3 + … + 10 =
  37. 37.1 + 3 + 5 + … + 35 =
  38. 38.1 + 2 + 3 + … + 32 =
  39. 39.1 + 3 + 5 + … + 25 =
  40. 40.1 + 2 + 3 + … + 6 =

Answer key

  1. 144
  2. 28
  3. 4186
  4. 36
  5. 210
  6. 1081
  7. 300
  8. 231
  9. 100
  10. 1830
  11. 120
  12. 361
  13. 78
  14. 496
  15. 1035
  16. 4656
  17. 4851
  18. 25
  19. 903
  20. 3160
  21. 625
  22. 3741
  23. 1953
  24. 400
  25. 2415
  26. 2485
  27. 105
  28. 1275
  29. 3570
  30. 2850
  31. 4095
  32. 45
  33. 1378
  34. 171
  35. 196
  36. 55
  37. 324
  38. 528
  39. 169
  40. 21

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