money-exchange calculates combinations of how to change a larger coin into smaller coins

money-exchange.scm

@@ -0,0 +1,14 @@
+(define (change amount kinds-of-coins)
+  (cond ((or (< amount 0) (= kinds-of-coins 0)) 0)
+		((= amount 0) 1)
+		(else (+ (change amount (- kinds-of-coins 1))
+			   (change (- amount (amount-wo-largest-coin kinds-of-coins)) kinds-of-coins)))))
+
+(define (amount-wo-largest-coin coins-left)
+  (cond ((= coins-left 5) 50)
+		((= coins-left 4) 25)
+		((= coins-left 3) 10)
+		((= coins-left 2) 5)
+		((= coins-left 1) 1)))
+
+(print (change 100 5))

newton.scm

@@ -19,4 +19,4 @@
 
 (define (sqrt x) (sqrt_iter (/ x 2.0) x x))
 
-(print (sqrt 2))
+(print (sqrt 10))