diff --git a/calculator.c b/calculator.c
index 832dfd2..3307f77 100644
--- a/calculator.c
+++ b/calculator.c
@@ -1,4 +1,4 @@
-#include <stdio.h>
+#nclude <stdio.h>
 
 void add(int a, int b)
 {
@@ -6,6 +6,7 @@ void add(int a, int b)
 }
 void sub()
 {
+	printf("a - b = %d\n", a - b);
 }
 void mul()
 {
@@ -40,4 +41,4 @@ int main(void)
         }
     }
     return 0;
-}
\ No newline at end of file
+}