Adjusting maths

guidelines/terms/22/perimeter.html

@@ -2,6 +2,6 @@
 <dd class="new">
 	<p class="change">New</p>	
    <p>continuous line forming the boundary of a shape not including shared pixels, or the <a>minimum bounding box</a>, whichever is shortest.</p>
-  <aside class="example"><p>The perimeter calculation for a 2 CSS pixel perimeter around a rectangle is 4<em>h</em>+4<em>w</em> -16, where <em>h</em> is the height and <em>w</em> is the width and the corners are not counted twice. For a 2 CSS pixel perimeter around a circle it is 4𝜋<em>r</em>.</p></aside>
+  <aside class="example"><p>The perimeter calculation for a 2 CSS pixel perimeter around a rectangle is 4<em>h</em>+4<em>w</em>, where <em>h</em> is the height and <em>w</em> is the width. For a 2 CSS pixel perimeter around a circle it is 4𝜋<em>r</em>.</p></aside>
 </dd>