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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 745 · 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 + … + 35 =
  2. 2.1 + 2 + 3 + … + 58 =
  3. 3.1 + 2 + 3 + … + 87 =
  4. 4.1 + 2 + 3 + … + 35 =
  5. 5.1 + 2 + 3 + … + 13 =
  6. 6.1 + 2 + 3 + … + 84 =
  7. 7.1 + 2 + 3 + … + 29 =
  8. 8.1 + 3 + 5 + … + 17 =
  9. 9.1 + 2 + 3 + … + 37 =
  10. 10.1 + 2 + 3 + … + 69 =
  11. 11.1 + 2 + 3 + … + 77 =
  12. 12.1 + 2 + 3 + … + 80 =
  13. 13.1 + 3 + 5 + … + 11 =
  14. 14.1 + 2 + 3 + … + 26 =
  15. 15.1 + 2 + 3 + … + 82 =
  16. 16.1 + 3 + 5 + … + 9 =
  17. 17.1 + 3 + 5 + … + 19 =
  18. 18.1 + 2 + 3 + … + 96 =
  19. 19.1 + 2 + 3 + … + 19 =
  20. 20.1 + 2 + 3 + … + 97 =
  21. 21.1 + 2 + 3 + … + 30 =
  22. 22.1 + 2 + 3 + … + 88 =
  23. 23.1 + 3 + 5 + … + 43 =
  24. 24.1 + 3 + 5 + … + 39 =
  25. 25.1 + 3 + 5 + … + 29 =
  26. 26.1 + 2 + 3 + … + 71 =
  27. 27.1 + 2 + 3 + … + 11 =
  28. 28.1 + 3 + 5 + … + 15 =
  29. 29.1 + 2 + 3 + … + 99 =
  30. 30.1 + 2 + 3 + … + 39 =
  31. 31.1 + 2 + 3 + … + 7 =
  32. 32.1 + 2 + 3 + … + 12 =
  33. 33.1 + 2 + 3 + … + 68 =
  34. 34.1 + 2 + 3 + … + 32 =
  35. 35.1 + 2 + 3 + … + 16 =
  36. 36.1 + 2 + 3 + … + 57 =
  37. 37.1 + 2 + 3 + … + 18 =
  38. 38.1 + 3 + 5 + … + 21 =
  39. 39.1 + 3 + 5 + … + 45 =
  40. 40.1 + 2 + 3 + … + 85 =

Answer key

  1. 324
  2. 1711
  3. 3828
  4. 630
  5. 91
  6. 3570
  7. 435
  8. 81
  9. 703
  10. 2415
  11. 3003
  12. 3240
  13. 36
  14. 351
  15. 3403
  16. 25
  17. 100
  18. 4656
  19. 190
  20. 4753
  21. 465
  22. 3916
  23. 484
  24. 400
  25. 225
  26. 2556
  27. 66
  28. 64
  29. 4950
  30. 780
  31. 28
  32. 78
  33. 2346
  34. 528
  35. 136
  36. 1653
  37. 171
  38. 121
  39. 529
  40. 3655

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