Regular expression for number and slash
<p>I do not know regular expressions and going crazy to find one that accepts formats consisting on numbers and slash. For example:</p>

<ul>
<li>5</li>
<li>5/10 </li>
<li>10/15/30 </li>
<li>10/20/120 </li>
<li>20/120/250/300</li>
</ul>