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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 185 · 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 + … + 12 =
  2. 2.1 + 2 + 3 + … + 54 =
  3. 3.1 + 2 + 3 + … + 92 =
  4. 4.1 + 2 + 3 + … + 65 =
  5. 5.1 + 3 + 5 + … + 33 =
  6. 6.1 + 3 + 5 + … + 43 =
  7. 7.1 + 2 + 3 + … + 84 =
  8. 8.1 + 3 + 5 + … + 9 =
  9. 9.1 + 2 + 3 + … + 15 =
  10. 10.1 + 2 + 3 + … + 95 =
  11. 11.1 + 3 + 5 + … + 37 =
  12. 12.1 + 3 + 5 + … + 27 =
  13. 13.1 + 3 + 5 + … + 47 =
  14. 14.1 + 3 + 5 + … + 45 =
  15. 15.1 + 2 + 3 + … + 35 =
  16. 16.1 + 3 + 5 + … + 29 =
  17. 17.1 + 2 + 3 + … + 45 =
  18. 18.1 + 2 + 3 + … + 68 =
  19. 19.1 + 3 + 5 + … + 19 =
  20. 20.1 + 2 + 3 + … + 70 =
  21. 21.1 + 3 + 5 + … + 25 =
  22. 22.1 + 2 + 3 + … + 23 =
  23. 23.1 + 2 + 3 + … + 10 =
  24. 24.1 + 3 + 5 + … + 41 =
  25. 25.1 + 2 + 3 + … + 59 =
  26. 26.1 + 2 + 3 + … + 28 =
  27. 27.1 + 2 + 3 + … + 69 =
  28. 28.1 + 2 + 3 + … + 57 =
  29. 29.1 + 2 + 3 + … + 97 =
  30. 30.1 + 2 + 3 + … + 14 =
  31. 31.1 + 2 + 3 + … + 61 =
  32. 32.1 + 2 + 3 + … + 32 =
  33. 33.1 + 2 + 3 + … + 75 =
  34. 34.1 + 3 + 5 + … + 17 =
  35. 35.1 + 3 + 5 + … + 11 =
  36. 36.1 + 2 + 3 + … + 64 =
  37. 37.1 + 2 + 3 + … + 25 =
  38. 38.1 + 2 + 3 + … + 62 =
  39. 39.1 + 2 + 3 + … + 85 =
  40. 40.1 + 2 + 3 + … + 31 =

Answer key

  1. 78
  2. 1485
  3. 4278
  4. 2145
  5. 289
  6. 484
  7. 3570
  8. 25
  9. 120
  10. 4560
  11. 361
  12. 196
  13. 576
  14. 529
  15. 630
  16. 225
  17. 1035
  18. 2346
  19. 100
  20. 2485
  21. 169
  22. 276
  23. 55
  24. 441
  25. 1770
  26. 406
  27. 2415
  28. 1653
  29. 4753
  30. 105
  31. 1891
  32. 528
  33. 2850
  34. 81
  35. 36
  36. 2080
  37. 325
  38. 1953
  39. 3655
  40. 496

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