diff --git a/collects/scheme/math.ss b/collects/scheme/math.ss
index 5c765b49d1..1a6c242f03 100644
--- a/collects/scheme/math.ss
+++ b/collects/scheme/math.ss
@@ -3,48 +3,32 @@
 ;; math.ss: some extra math routines
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-(module math scheme/base
-  (provide euler
-           pi 
-           sqr
-           sgn conjugate
-           sinh cosh)
+#lang scheme/base
+(provide euler
+         pi
+         sqr
+         sgn conjugate
+         sinh cosh)
 
-  (define (sqr z) (* z z))
-  
-  ;; circular constants and aliases
-  (define euler (exp 1.0)) 
-  (define pi (atan 0 -1))
-  
-  ;; sgn function 
-  (define sgn
-    (lambda (x)
-      (if (exact? x)
-	  (cond
-	   ((< x 0) -1)
-	   ((> x 0)  1)
-	   (else 0))
-	  (cond
-	   ((< x 0.0) -1.0)
-	   ((> x 0.0)  1.0)
-	   (else 0.0)))))
-  
-  ;; complex conjugate
-  (define conjugate
-    (lambda (z)
-      (make-rectangular 
-       (real-part z)
-       (- (imag-part z)))))
-  
-  ;; real hyperbolic functions
-  (define sinh 
-    (lambda (x)
-      (/
-       (- (exp x) (exp (- x)))
-       2.0)))
-  
-  (define cosh
-    (lambda (x)
-      (/
-       (+ (exp x) (exp (- x)))
-       2.0))))
+(define (sqr z) (* z z))
+
+;; circular constants and aliases
+(define euler (exp 1.0))
+(define pi (atan 0 -1))
+
+;; sgn function
+(define (sgn x)
+  (if (exact? x)
+    (cond [(< x 0) -1] [(> x 0) 1] [else 0])
+    (cond [(< x 0.0) -1.0] [(> x 0.0) 1.0] [else 0.0])))
+
+;; complex conjugate
+(define (conjugate z)
+  (make-rectangular (real-part z) (- (imag-part z))))
+
+;; real hyperbolic functions
+(define (sinh x)
+  (/ (- (exp x) (exp (- x))) 2.0))
+
+(define (cosh x)
+  (/ (+ (exp x) (exp (- x))) 2.0))