the factorial of  1  is  1
the factorial of  2  is  2
the factorial of  3  is  6
the factorial of  4  is  24
the factorial of  5  is  120
the factorial of  6  is  720
the factorial of  7  is  5040
the factorial of  8  is  40320
the factorial of  9  is  362880
the factorial of  10  is  3628800
