diff --git a/examples/arithmetics.pegjs b/examples/arithmetics.pegjs
index ef70564..7d4dea8 100644
--- a/examples/arithmetics.pegjs
+++ b/examples/arithmetics.pegjs
@@ -24,7 +24,7 @@ Factor
   / Integer
 
 Integer "integer"
-  = [0-9]+ { return parseInt(text(), 10); }
+  = _ [0-9]+ { return parseInt(text(), 10); }
 
 _ "whitespace"
   = [ \t\n\r]*