← 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 200 · 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 + … + 49 =
  2. 2.1 + 3 + 5 + … + 43 =
  3. 3.1 + 2 + 3 + … + 40 =
  4. 4.1 + 2 + 3 + … + 19 =
  5. 5.1 + 3 + 5 + … + 19 =
  6. 6.1 + 3 + 5 + … + 39 =
  7. 7.1 + 2 + 3 + … + 64 =
  8. 8.1 + 3 + 5 + … + 33 =
  9. 9.1 + 2 + 3 + … + 76 =
  10. 10.1 + 2 + 3 + … + 27 =
  11. 11.1 + 2 + 3 + … + 62 =
  12. 12.1 + 2 + 3 + … + 30 =
  13. 13.1 + 2 + 3 + … + 73 =
  14. 14.1 + 2 + 3 + … + 11 =
  15. 15.1 + 3 + 5 + … + 17 =
  16. 16.1 + 3 + 5 + … + 11 =
  17. 17.1 + 2 + 3 + … + 36 =
  18. 18.1 + 2 + 3 + … + 20 =
  19. 19.1 + 2 + 3 + … + 56 =
  20. 20.1 + 2 + 3 + … + 6 =
  21. 21.1 + 2 + 3 + … + 45 =
  22. 22.1 + 2 + 3 + … + 84 =
  23. 23.1 + 2 + 3 + … + 81 =
  24. 24.1 + 3 + 5 + … + 21 =
  25. 25.1 + 2 + 3 + … + 59 =
  26. 26.1 + 2 + 3 + … + 60 =
  27. 27.1 + 2 + 3 + … + 14 =
  28. 28.1 + 2 + 3 + … + 42 =
  29. 29.1 + 2 + 3 + … + 61 =
  30. 30.1 + 2 + 3 + … + 80 =
  31. 31.1 + 2 + 3 + … + 13 =
  32. 32.1 + 2 + 3 + … + 15 =
  33. 33.1 + 3 + 5 + … + 29 =
  34. 34.1 + 3 + 5 + … + 27 =
  35. 35.1 + 2 + 3 + … + 79 =
  36. 36.1 + 2 + 3 + … + 68 =
  37. 37.1 + 2 + 3 + … + 92 =
  38. 38.1 + 2 + 3 + … + 77 =
  39. 39.1 + 2 + 3 + … + 97 =
  40. 40.1 + 2 + 3 + … + 71 =

Answer key

  1. 625
  2. 484
  3. 820
  4. 190
  5. 100
  6. 400
  7. 2080
  8. 289
  9. 2926
  10. 378
  11. 1953
  12. 465
  13. 2701
  14. 66
  15. 81
  16. 36
  17. 666
  18. 210
  19. 1596
  20. 21
  21. 1035
  22. 3570
  23. 3321
  24. 121
  25. 1770
  26. 1830
  27. 105
  28. 903
  29. 1891
  30. 3240
  31. 91
  32. 120
  33. 225
  34. 196
  35. 3160
  36. 2346
  37. 4278
  38. 3003
  39. 4753
  40. 2556

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