diff --git a/readme13-15.md b/readme13-15.md
index 420c706..a8c6c34 100644
--- a/readme13-15.md
+++ b/readme13-15.md
@@ -133,6 +133,7 @@ two_power_of_five = power(2)(5) # 32
 ```
 
 ## Built-in Higher Order Functions
+not ready yet 
 
 ## Exercises: Day 13