diff --git a/lectures/scala_lecture_5.html b/lectures/scala_lecture_5.html
index 4c69602e..af2d42df 100644
--- a/lectures/scala_lecture_5.html
+++ b/lectures/scala_lecture_5.html
@@ -343,7 +343,7 @@ <h2>Monoid (моноид)</h2>
   }
 
   implicit val doubleMonoid: Monoid[Double] = new Monoid[Double] {
-    override def empty: Double = 0
+    override def empty: Double = 1
     override def combine(x: Double, y: Double): Double = x * y
   }