diff --git a/5_Software/math_lib.py b/5_Software/math_lib.py
index 2095a38..e2329ac 100644
--- a/5_Software/math_lib.py
+++ b/5_Software/math_lib.py
@@ -32,3 +32,4 @@ def square_root(x):
         else:
             right = guess
         guess = (right+left)/2.0
+    return guess