diff --git a/src/lab/arith.php b/src/lab/arith.php
index b31e2d13..04efa016 100644
--- a/src/lab/arith.php
+++ b/src/lab/arith.php
@@ -365,10 +365,10 @@ function confirmTo(url) {
 </div>
 			<div class="menu">
 <ul>
-<li><a href="objective.php?exp=arith" target="_self" >Objective</a>
-</li>
 <li><a href="intro.php?exp=arith" target="_self" >Introduction</a>
 </li>
+<li><a href="objective.php?exp=arith" target="_self" >Objective</a>
+</li>
 <li><a href="theory.php?exp=arith" target="_self" >Theory</a>
 </li>
 <li><a href="procedure.php?exp=arith" target="_self" >Procedure</a>