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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 713 · 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 + … + 49 =
  2. 2.1 + 3 + 5 + … + 31 =
  3. 3.1 + 3 + 5 + … + 45 =
  4. 4.1 + 2 + 3 + … + 69 =
  5. 5.1 + 2 + 3 + … + 42 =
  6. 6.1 + 2 + 3 + … + 6 =
  7. 7.1 + 2 + 3 + … + 97 =
  8. 8.1 + 2 + 3 + … + 47 =
  9. 9.1 + 3 + 5 + … + 19 =
  10. 10.1 + 3 + 5 + … + 9 =
  11. 11.1 + 2 + 3 + … + 54 =
  12. 12.1 + 3 + 5 + … + 39 =
  13. 13.1 + 2 + 3 + … + 48 =
  14. 14.1 + 2 + 3 + … + 75 =
  15. 15.1 + 2 + 3 + … + 50 =
  16. 16.1 + 3 + 5 + … + 15 =
  17. 17.1 + 2 + 3 + … + 70 =
  18. 18.1 + 2 + 3 + … + 91 =
  19. 19.1 + 2 + 3 + … + 59 =
  20. 20.1 + 2 + 3 + … + 23 =
  21. 21.1 + 2 + 3 + … + 62 =
  22. 22.1 + 2 + 3 + … + 86 =
  23. 23.1 + 2 + 3 + … + 44 =
  24. 24.1 + 3 + 5 + … + 47 =
  25. 25.1 + 2 + 3 + … + 18 =
  26. 26.1 + 2 + 3 + … + 25 =
  27. 27.1 + 2 + 3 + … + 84 =
  28. 28.1 + 2 + 3 + … + 14 =
  29. 29.1 + 3 + 5 + … + 21 =
  30. 30.1 + 3 + 5 + … + 29 =
  31. 31.1 + 3 + 5 + … + 17 =
  32. 32.1 + 2 + 3 + … + 31 =
  33. 33.1 + 2 + 3 + … + 64 =
  34. 34.1 + 2 + 3 + … + 24 =
  35. 35.1 + 2 + 3 + … + 10 =
  36. 36.1 + 2 + 3 + … + 63 =
  37. 37.1 + 2 + 3 + … + 21 =
  38. 38.1 + 2 + 3 + … + 45 =
  39. 39.1 + 2 + 3 + … + 7 =
  40. 40.1 + 2 + 3 + … + 94 =

Answer key

  1. 625
  2. 256
  3. 529
  4. 2415
  5. 903
  6. 21
  7. 4753
  8. 1128
  9. 100
  10. 25
  11. 1485
  12. 400
  13. 1176
  14. 2850
  15. 1275
  16. 64
  17. 2485
  18. 4186
  19. 1770
  20. 276
  21. 1953
  22. 3741
  23. 990
  24. 576
  25. 171
  26. 325
  27. 3570
  28. 105
  29. 121
  30. 225
  31. 81
  32. 496
  33. 2080
  34. 300
  35. 55
  36. 2016
  37. 231
  38. 1035
  39. 28
  40. 4465

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