An interesting consequence of the binomial theorem is obtained by setting both variables x and y equal to one. In this case, we know that (1 + 1)n = 2n, and so
{displaystyle {n choose 0}+{n choose 1}+cdots +{n choose n-1}+{n choose n}=2^{n}.} {n choose 0}+{n choose 1}+cdots +{n choose n-1}+{n choose n}=2^{n}.