← 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 906 · 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 + … + 51 =
  2. 2.1 + 2 + 3 + … + 43 =
  3. 3.1 + 2 + 3 + … + 52 =
  4. 4.1 + 2 + 3 + … + 6 =
  5. 5.1 + 3 + 5 + … + 13 =
  6. 6.1 + 3 + 5 + … + 9 =
  7. 7.1 + 2 + 3 + … + 31 =
  8. 8.1 + 2 + 3 + … + 74 =
  9. 9.1 + 3 + 5 + … + 25 =
  10. 10.1 + 2 + 3 + … + 30 =
  11. 11.1 + 2 + 3 + … + 9 =
  12. 12.1 + 3 + 5 + … + 17 =
  13. 13.1 + 3 + 5 + … + 27 =
  14. 14.1 + 3 + 5 + … + 19 =
  15. 15.1 + 2 + 3 + … + 14 =
  16. 16.1 + 3 + 5 + … + 43 =
  17. 17.1 + 2 + 3 + … + 98 =
  18. 18.1 + 2 + 3 + … + 47 =
  19. 19.1 + 3 + 5 + … + 37 =
  20. 20.1 + 2 + 3 + … + 70 =
  21. 21.1 + 3 + 5 + … + 29 =
  22. 22.1 + 2 + 3 + … + 73 =
  23. 23.1 + 2 + 3 + … + 68 =
  24. 24.1 + 2 + 3 + … + 87 =
  25. 25.1 + 2 + 3 + … + 90 =
  26. 26.1 + 2 + 3 + … + 45 =
  27. 27.1 + 3 + 5 + … + 39 =
  28. 28.1 + 2 + 3 + … + 100 =
  29. 29.1 + 2 + 3 + … + 59 =
  30. 30.1 + 2 + 3 + … + 72 =
  31. 31.1 + 2 + 3 + … + 77 =
  32. 32.1 + 2 + 3 + … + 75 =
  33. 33.1 + 2 + 3 + … + 57 =
  34. 34.1 + 2 + 3 + … + 8 =
  35. 35.1 + 2 + 3 + … + 46 =
  36. 36.1 + 2 + 3 + … + 61 =
  37. 37.1 + 3 + 5 + … + 15 =
  38. 38.1 + 3 + 5 + … + 47 =
  39. 39.1 + 3 + 5 + … + 41 =
  40. 40.1 + 2 + 3 + … + 82 =

Answer key

  1. 1326
  2. 946
  3. 1378
  4. 21
  5. 49
  6. 25
  7. 496
  8. 2775
  9. 169
  10. 465
  11. 45
  12. 81
  13. 196
  14. 100
  15. 105
  16. 484
  17. 4851
  18. 1128
  19. 361
  20. 2485
  21. 225
  22. 2701
  23. 2346
  24. 3828
  25. 4095
  26. 1035
  27. 400
  28. 5050
  29. 1770
  30. 2628
  31. 3003
  32. 2850
  33. 1653
  34. 36
  35. 1081
  36. 1891
  37. 64
  38. 576
  39. 441
  40. 3403

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