diff --git a/libs/plugins/function.math.php b/libs/plugins/function.math.php
index d7ac9f8f..257d2fee 100644
--- a/libs/plugins/function.math.php
+++ b/libs/plugins/function.math.php
@@ -39,7 +39,7 @@ function smarty_function_math($params, $smarty, $template)
     }
 
     // match all vars in equation, make sure all are passed
-    preg_match_all("!(?:0x[a-fA-F0-9]+)|([a-zA-Z][a-zA-Z0-9_]+)!",$equation, $match);
+    preg_match_all("!(?:0x[a-fA-F0-9]+)|([a-zA-Z][a-zA-Z0-9_]*)!",$equation, $match);
     $allowed_funcs = array('int','abs','ceil','cos','exp','floor','log','log10',
                            'max','min','pi','pow','rand','round','sin','sqrt','srand','tan');
     
@@ -81,4 +81,4 @@ function smarty_function_math($params, $smarty, $template)
         }
     }
 }
-?>
+?>
\ No newline at end of file