(define factorial
     (lambda (n)
       (num-times-range 1 1 n)))

   |(factorial 5)
   |(num-times-range 1 1 5)
   |(num-times-range 1 2 5)
   |(num-times-range 2 3 5)
   |(num-times-range 6 4 5)
   |(num-times-range 24 5 5)
   |(num-times-range 120 6 5)
   |120
   120