diff --git a/functions.py b/functions.py
index cb7551c..cbed543 100644
--- a/functions.py
+++ b/functions.py
@@ -2,8 +2,9 @@ def add(a, b):
     return a + b
 
 
-def subtract(a, b):
-    return a - b
+## corrected with substract sign
+def substract(a, b):
+      return a-b
 
 
 def multiply(a, b):
@@ -11,4 +12,8 @@ def multiply(a, b):
 
 
 def convert_fahrenheit_to_celsius(fahrenheit):
-    return multiply(subtract(fahrenheit, 32), 9 / 5)
+    return multiply(substract(fahrenheit, 32), 5 / 9) ## corrected  the with right formula
+
+
+
+print(convert_fahrenheit_to_celsius(273))