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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 732 · 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 + … + 62 =
  2. 2.1 + 2 + 3 + … + 8 =
  3. 3.1 + 2 + 3 + … + 61 =
  4. 4.1 + 2 + 3 + … + 90 =
  5. 5.1 + 2 + 3 + … + 64 =
  6. 6.1 + 3 + 5 + … + 23 =
  7. 7.1 + 2 + 3 + … + 63 =
  8. 8.1 + 2 + 3 + … + 87 =
  9. 9.1 + 2 + 3 + … + 47 =
  10. 10.1 + 2 + 3 + … + 21 =
  11. 11.1 + 2 + 3 + … + 77 =
  12. 12.1 + 2 + 3 + … + 36 =
  13. 13.1 + 2 + 3 + … + 33 =
  14. 14.1 + 2 + 3 + … + 44 =
  15. 15.1 + 2 + 3 + … + 95 =
  16. 16.1 + 2 + 3 + … + 65 =
  17. 17.1 + 3 + 5 + … + 29 =
  18. 18.1 + 3 + 5 + … + 41 =
  19. 19.1 + 2 + 3 + … + 14 =
  20. 20.1 + 2 + 3 + … + 13 =
  21. 21.1 + 3 + 5 + … + 47 =
  22. 22.1 + 2 + 3 + … + 85 =
  23. 23.1 + 2 + 3 + … + 97 =
  24. 24.1 + 2 + 3 + … + 12 =
  25. 25.1 + 2 + 3 + … + 56 =
  26. 26.1 + 3 + 5 + … + 19 =
  27. 27.1 + 3 + 5 + … + 33 =
  28. 28.1 + 2 + 3 + … + 24 =
  29. 29.1 + 2 + 3 + … + 16 =
  30. 30.1 + 3 + 5 + … + 21 =
  31. 31.1 + 2 + 3 + … + 94 =
  32. 32.1 + 2 + 3 + … + 32 =
  33. 33.1 + 2 + 3 + … + 96 =
  34. 34.1 + 2 + 3 + … + 82 =
  35. 35.1 + 2 + 3 + … + 76 =
  36. 36.1 + 2 + 3 + … + 48 =
  37. 37.1 + 2 + 3 + … + 80 =
  38. 38.1 + 2 + 3 + … + 68 =
  39. 39.1 + 3 + 5 + … + 45 =
  40. 40.1 + 2 + 3 + … + 23 =

Answer key

  1. 1953
  2. 36
  3. 1891
  4. 4095
  5. 2080
  6. 144
  7. 2016
  8. 3828
  9. 1128
  10. 231
  11. 3003
  12. 666
  13. 561
  14. 990
  15. 4560
  16. 2145
  17. 225
  18. 441
  19. 105
  20. 91
  21. 576
  22. 3655
  23. 4753
  24. 78
  25. 1596
  26. 100
  27. 289
  28. 300
  29. 136
  30. 121
  31. 4465
  32. 528
  33. 4656
  34. 3403
  35. 2926
  36. 1176
  37. 3240
  38. 2346
  39. 529
  40. 276

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