formatting

subjects/gcd.md

@@ -1,15 +1,16 @@
-# gcd
-## Instructions
+## gcd
+
+### Instructions
 
 Write a program that takes two strings representing two strictly positive
 integers that fit in an int.
 
-Display their greatest common divisor followed by a newline (It's always a
+Display their greatest common divisor followed by a newline (It is always a
 strictly positive integer).
 
 If the number of parameters is not 2, display a newline.
 
-## Expected output
+Example of output :
 
 ```console
 student@ubuntu:~/student/gcd$ go build