What does `$page -= 1` in my PHP document mean?
<p>I have the following variable defined in a PHP document I am working with, and I'm unsure what it means.</p>

<p><strong>The PHP</strong></p>

<pre><code>$page -= 1;
</code></pre>

<p>The part I am unsure of is the <code>-=</code></p>

<p>Thanks!</p>
