Exercise 3.1

Approach: Define an iterative procedure that computes:
	   A × (low × ... × high)     [P]

   (define num-times-range
     (lambda (a low high)
       (if _________________  ; What is the relation between low and high
	   _________________  ; when the procedure stops?
           _________________)))
Example:
   (num-times-range 5 3 6) => 1800