When making a number combination from {1,2,3,4,5},
there are 2 choices for the 1, use it in the combination or don't use it.
there are 2 choices for the 2, use it in the combination or don't use it.
there are 2 choices for the 3, use it in the combination or don't use it.
there are 2 choices for the 4, use it in the combination or don't use it.
there are 2 choices for the 5, use it in the combination or don't use it.
That's 2 = 25 = 32
1. {1,2,3,4,5}
2. {1,2,3,4}
3. {1,2,3,5}
4. {1,2,3}
5. {1,2,4,5}
6. {1,2,4}
7. {1,2,5}
8. {1,2}
9. {1,3,4,5}
10. {1,3,4}
11. {1,3,5}
12. {1,3}
13. {1,4,5}
14. {1,4}
15. {1,5}
16. {1}
17. {2,3,4,5}
18. {2,3,4}
19. {2,3,5}
20. {2,3}
21. {2,4,5}
22. {2,4}
23. {2,5}
24. {2}
25. {3,4,5}
26. {3,4}
27. {3,5}
28. {3}
29. {4,5}
30. {4}
31. {5}
32. {}
Notice that the 32nd combination
is a combination of NONE AT ALL!!!
Edwin