diff --git a/calculator.c b/calculator.c
index 832dfd2..0a507e6 100644
--- a/calculator.c
+++ b/calculator.c
@@ -4,11 +4,13 @@ void add(int a, int b)
 {
     printf("a + b = %d\n", a + b);
 }
-void sub()
+void sub(int a, int b)
 {
+    printf("%d ", a-b);
 }
-void mul()
+void mul(int a, int b)
 {
+    printf("%d\n", a*b);
 }
 void div()
 {