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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 888 · 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 + … + 23 =
  2. 2.1 + 2 + 3 + … + 48 =
  3. 3.1 + 2 + 3 + … + 97 =
  4. 4.1 + 3 + 5 + … + 31 =
  5. 5.1 + 2 + 3 + … + 84 =
  6. 6.1 + 2 + 3 + … + 61 =
  7. 7.1 + 2 + 3 + … + 77 =
  8. 8.1 + 3 + 5 + … + 33 =
  9. 9.1 + 3 + 5 + … + 43 =
  10. 10.1 + 2 + 3 + … + 92 =
  11. 11.1 + 2 + 3 + … + 63 =
  12. 12.1 + 2 + 3 + … + 25 =
  13. 13.1 + 2 + 3 + … + 57 =
  14. 14.1 + 2 + 3 + … + 86 =
  15. 15.1 + 2 + 3 + … + 9 =
  16. 16.1 + 2 + 3 + … + 94 =
  17. 17.1 + 2 + 3 + … + 14 =
  18. 18.1 + 2 + 3 + … + 67 =
  19. 19.1 + 3 + 5 + … + 27 =
  20. 20.1 + 2 + 3 + … + 17 =
  21. 21.1 + 2 + 3 + … + 60 =
  22. 22.1 + 3 + 5 + … + 25 =
  23. 23.1 + 2 + 3 + … + 43 =
  24. 24.1 + 2 + 3 + … + 56 =
  25. 25.1 + 2 + 3 + … + 81 =
  26. 26.1 + 2 + 3 + … + 78 =
  27. 27.1 + 2 + 3 + … + 66 =
  28. 28.1 + 2 + 3 + … + 64 =
  29. 29.1 + 3 + 5 + … + 49 =
  30. 30.1 + 2 + 3 + … + 26 =
  31. 31.1 + 2 + 3 + … + 75 =
  32. 32.1 + 3 + 5 + … + 15 =
  33. 33.1 + 3 + 5 + … + 37 =
  34. 34.1 + 2 + 3 + … + 87 =
  35. 35.1 + 2 + 3 + … + 70 =
  36. 36.1 + 2 + 3 + … + 24 =
  37. 37.1 + 3 + 5 + … + 9 =
  38. 38.1 + 2 + 3 + … + 33 =
  39. 39.1 + 3 + 5 + … + 17 =
  40. 40.1 + 3 + 5 + … + 13 =

Answer key

  1. 144
  2. 1176
  3. 4753
  4. 256
  5. 3570
  6. 1891
  7. 3003
  8. 289
  9. 484
  10. 4278
  11. 2016
  12. 325
  13. 1653
  14. 3741
  15. 45
  16. 4465
  17. 105
  18. 2278
  19. 196
  20. 153
  21. 1830
  22. 169
  23. 946
  24. 1596
  25. 3321
  26. 3081
  27. 2211
  28. 2080
  29. 625
  30. 351
  31. 2850
  32. 64
  33. 361
  34. 3828
  35. 2485
  36. 300
  37. 25
  38. 561
  39. 81
  40. 49

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