diff --git a/Demo/classes/Rat.py b/Demo/classes/Rat.py
index 5273e3230b9..4fc4a1786f1 100755
--- a/Demo/classes/Rat.py
+++ b/Demo/classes/Rat.py
@@ -100,7 +100,7 @@ class Rat:
 		if self.__den == 1:
 			return str(self.__num)
 		else:
-			return '%s/%s' % (str(self.__num), str(self.__den))
+			return '(%s/%s)' % (str(self.__num), str(self.__den))
 
 	# a + b
 	def __add__(a, b):
@@ -213,7 +213,7 @@ class Rat:
 
 	# cmp(a,b)
 	def __cmp__(a, b):
-		diff = a - b
+		diff = Rat(a - b)
 		if diff.__num < 0:
 			return -1
 		elif diff.__num > 0:
@@ -244,16 +244,16 @@ def test():
 	[Rat(1,2), Rat(-3,10), Rat(1,25), Rat(1,4)]
 	[Rat(-3,10), Rat(1,25), Rat(1,4), Rat(1,2)]
 	0
-	11/10
-	11/10
+	(11/10)
+	(11/10)
 	1.1
 	OK
-	2 1.5 3/2 (1.5+1.5j) 15707963/5000000
+	2 1.5 (3/2) (1.5+1.5j) (15707963/5000000)
 	2 2 2.0 (2+0j)
 
 	4 0 4 1 4 0
 	3.5 0.5 3.0 1.33333333333 2.82842712475 1
-	7/2 1/2 3 4/3 2.82842712475 1
+	(7/2) (1/2) 3 (4/3) 2.82842712475 1
 	(3.5+1.5j) (0.5-1.5j) (3+3j) (0.666666666667-0.666666666667j) (1.43248815986+2.43884761145j) 1
 	1.5 1 1.5 (1.5+0j)
 
@@ -261,11 +261,11 @@ def test():
 	3.0 0.0 2.25 1.0 1.83711730709 0
 	3.0 0.0 2.25 1.0 1.83711730709 1
 	(3+1.5j) -1.5j (2.25+2.25j) (0.5-0.5j) (1.50768393746+1.04970907623j) -1
-	3/2 1 1.5 (1.5+0j)
+	(3/2) 1 1.5 (1.5+0j)
 
-	7/2 -1/2 3 3/4 9/4 -1
+	(7/2) (-1/2) 3 (3/4) (9/4) -1
 	3.0 0.0 2.25 1.0 1.83711730709 -1
-	3 0 9/4 1 1.83711730709 0
+	3 0 (9/4) 1 1.83711730709 0
 	(3+1.5j) -1.5j (2.25+2.25j) (0.5-0.5j) (1.50768393746+1.04970907623j) -1
 	(1.5+1.5j) (1.5+1.5j)