In how many ways can you choose one or more of 12 different candies?

Each candy can be dealt with in two ways.It can be chosen or not chosen.This will give 2 possibilites for the first candy, 2 for the second, and so on.by multiplying the cases together we get $212$. Since the case of no candy being selected is not an option, we have to subtract 1 from our answer.

Therefore,there are $212$- 1 = 4095 ways of selecting one or more candies