diff --git a/README.md b/README.md
index 8af61a0..ea6d31b 100644
--- a/README.md
+++ b/README.md
@@ -107,8 +107,10 @@ $executor->addOperator('MyNamespace\ModulusToken');
 
 Default variables:
 
+```
 $pi = 3.14159265359
 $e = 2.71828182846
+```
 
 You can add own variable to executor: