diff --git a/demo4.py b/demo4.py
new file mode 100644
index 0000000..aabfecf
--- /dev/null
+++ b/demo4.py
@@ -0,0 +1,3 @@
+a=10
+b=20
+print (a-b)
diff --git a/test.py b/test.py
index 0c94276..9928d73 100644
--- a/test.py
+++ b/test.py
@@ -1,3 +1,3 @@
-a=10
+a=1000
 b=20
-print (a+b)
\ No newline at end of file
+print (a-b)