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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 372 · 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 + … + 16 =
  2. 2.1 + 2 + 3 + … + 74 =
  3. 3.1 + 2 + 3 + … + 38 =
  4. 4.1 + 2 + 3 + … + 12 =
  5. 5.1 + 2 + 3 + … + 87 =
  6. 6.1 + 2 + 3 + … + 94 =
  7. 7.1 + 3 + 5 + … + 37 =
  8. 8.1 + 3 + 5 + … + 25 =
  9. 9.1 + 3 + 5 + … + 27 =
  10. 10.1 + 2 + 3 + … + 9 =
  11. 11.1 + 3 + 5 + … + 17 =
  12. 12.1 + 2 + 3 + … + 26 =
  13. 13.1 + 2 + 3 + … + 60 =
  14. 14.1 + 2 + 3 + … + 51 =
  15. 15.1 + 3 + 5 + … + 43 =
  16. 16.1 + 3 + 5 + … + 13 =
  17. 17.1 + 3 + 5 + … + 39 =
  18. 18.1 + 2 + 3 + … + 33 =
  19. 19.1 + 2 + 3 + … + 85 =
  20. 20.1 + 2 + 3 + … + 41 =
  21. 21.1 + 2 + 3 + … + 61 =
  22. 22.1 + 3 + 5 + … + 19 =
  23. 23.1 + 2 + 3 + … + 65 =
  24. 24.1 + 3 + 5 + … + 11 =
  25. 25.1 + 2 + 3 + … + 32 =
  26. 26.1 + 2 + 3 + … + 83 =
  27. 27.1 + 2 + 3 + … + 73 =
  28. 28.1 + 2 + 3 + … + 62 =
  29. 29.1 + 2 + 3 + … + 98 =
  30. 30.1 + 2 + 3 + … + 90 =
  31. 31.1 + 3 + 5 + … + 21 =
  32. 32.1 + 2 + 3 + … + 6 =
  33. 33.1 + 2 + 3 + … + 40 =
  34. 34.1 + 3 + 5 + … + 35 =
  35. 35.1 + 3 + 5 + … + 33 =
  36. 36.1 + 2 + 3 + … + 43 =
  37. 37.1 + 2 + 3 + … + 13 =
  38. 38.1 + 2 + 3 + … + 89 =
  39. 39.1 + 2 + 3 + … + 69 =
  40. 40.1 + 2 + 3 + … + 76 =

Answer key

  1. 136
  2. 2775
  3. 741
  4. 78
  5. 3828
  6. 4465
  7. 361
  8. 169
  9. 196
  10. 45
  11. 81
  12. 351
  13. 1830
  14. 1326
  15. 484
  16. 49
  17. 400
  18. 561
  19. 3655
  20. 861
  21. 1891
  22. 100
  23. 2145
  24. 36
  25. 528
  26. 3486
  27. 2701
  28. 1953
  29. 4851
  30. 4095
  31. 121
  32. 21
  33. 820
  34. 324
  35. 289
  36. 946
  37. 91
  38. 4005
  39. 2415
  40. 2926

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