How do you simplify numbers with exponents?

A number with an exponent can be simplified by multiplying it out; 53 = 5 * 5 * 5 = 125. It is helpful to remember the values of some common exponents, especially powers of 2 (22 = 4, 23 = 8, 24 = 16, 25 = 32, etc) so that you do not have to calculate them again each time you encounter them.