If you have a set of $N$ items, how many subsets can you make? For example, for the set existing of $3$ items (Item1, Item2 and Item3) the subsets are Item1, Item2, Item3, Item2+3, Item1+2, Item1+3 and Item1+2+3. Is there a general formula for this?
I think it might be $2^N-1$, but I'm not sure.
Thank you in advance!