# What is the proof that the total number of subsets of a set is 2n2^n? [closed]

What is the proof that given a set of $n$ elements there are $2^n$ possible subsets (including the empty-set and the original set).

Remark: this works also for the empty set. An empty set has exactly one subset, namely the empty set. And the fact that $2^0=1$ reflects the fact that there is only one way to pick no elements at all!