diff --git a/parts/2/notes.md b/parts/2/notes.md
index c9a686c..b40bc2f 100644
--- a/parts/2/notes.md
+++ b/parts/2/notes.md
@@ -11,3 +11,4 @@ Exercises:
 * [X] 2.10
 * [X] 2.11
 * [X] 2.12
+* [X] 2.13