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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 994 · 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 + … + 17 =
  2. 2.1 + 2 + 3 + … + 97 =
  3. 3.1 + 2 + 3 + … + 61 =
  4. 4.1 + 3 + 5 + … + 37 =
  5. 5.1 + 3 + 5 + … + 41 =
  6. 6.1 + 3 + 5 + … + 35 =
  7. 7.1 + 3 + 5 + … + 11 =
  8. 8.1 + 3 + 5 + … + 17 =
  9. 9.1 + 2 + 3 + … + 68 =
  10. 10.1 + 3 + 5 + … + 47 =
  11. 11.1 + 3 + 5 + … + 27 =
  12. 12.1 + 2 + 3 + … + 26 =
  13. 13.1 + 2 + 3 + … + 36 =
  14. 14.1 + 2 + 3 + … + 51 =
  15. 15.1 + 2 + 3 + … + 69 =
  16. 16.1 + 3 + 5 + … + 33 =
  17. 17.1 + 3 + 5 + … + 43 =
  18. 18.1 + 2 + 3 + … + 91 =
  19. 19.1 + 2 + 3 + … + 78 =
  20. 20.1 + 3 + 5 + … + 23 =
  21. 21.1 + 3 + 5 + … + 19 =
  22. 22.1 + 3 + 5 + … + 15 =
  23. 23.1 + 2 + 3 + … + 8 =
  24. 24.1 + 3 + 5 + … + 13 =
  25. 25.1 + 2 + 3 + … + 96 =
  26. 26.1 + 2 + 3 + … + 55 =
  27. 27.1 + 2 + 3 + … + 56 =
  28. 28.1 + 2 + 3 + … + 35 =
  29. 29.1 + 2 + 3 + … + 38 =
  30. 30.1 + 3 + 5 + … + 21 =
  31. 31.1 + 2 + 3 + … + 11 =
  32. 32.1 + 2 + 3 + … + 7 =
  33. 33.1 + 2 + 3 + … + 30 =
  34. 34.1 + 3 + 5 + … + 29 =
  35. 35.1 + 2 + 3 + … + 70 =
  36. 36.1 + 2 + 3 + … + 59 =
  37. 37.1 + 2 + 3 + … + 65 =
  38. 38.1 + 2 + 3 + … + 75 =
  39. 39.1 + 3 + 5 + … + 31 =
  40. 40.1 + 2 + 3 + … + 15 =

Answer key

  1. 153
  2. 4753
  3. 1891
  4. 361
  5. 441
  6. 324
  7. 36
  8. 81
  9. 2346
  10. 576
  11. 196
  12. 351
  13. 666
  14. 1326
  15. 2415
  16. 289
  17. 484
  18. 4186
  19. 3081
  20. 144
  21. 100
  22. 64
  23. 36
  24. 49
  25. 4656
  26. 1540
  27. 1596
  28. 630
  29. 741
  30. 121
  31. 66
  32. 28
  33. 465
  34. 225
  35. 2485
  36. 1770
  37. 2145
  38. 2850
  39. 256
  40. 120

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