diff --git a/source/chapter2/21_Protocols.md b/source/chapter2/21_Protocols.md
index e1173fce..2913eb9a 100755
--- a/source/chapter2/21_Protocols.md
+++ b/source/chapter2/21_Protocols.md
@@ -230,7 +230,7 @@ class Dice {
 		self.generator = generator
 	}
 	func roll() -> Int {
-		return Int(generator.random() * Double(sides)) +1
+		return Int(generator.random() * Double(sides)) + 1
 	}
 }
 ```