Intermediate Algebra for College Students (7th Edition)

when n = 0, $b^{0}$ = 1 when n = 1, $b^{1}$ = b when n = 2, $b^{2}$ = b x b when n = 3 $b^{3}$ = b x b x b
Assuming that n is a natural number, $b^{n}$ would then refer to the variable b multiplying itself by n number of times.