For an integer k that is greater than or equal to 1, k! (pronounced "k factorial") is k×(k−1)×(k−2)× …×1. By convention, 0! = 1. There are k! ways of ordering k distinct objects. For example, 9! is the number of batting orders of 9 baseball players, and 52! is the number of different ways a standard deck of playing cards can be ordered. The calculator above has a button to compute the factorial of a number. To compute k!, first type the value of k, then press the button labeled "!".