title: How can I insert a decimal point before the last three digits of a number?
body: <p>I have a number and need to add a decimal to it for formatting.</p>
  
  <p>The number is guaranteed to be between 1000 and 999999 (I have covered the other possibilities in other ways, this is the one I can't get my head around). I need to put a decimal before the last 3 digits, for example:</p>
  
  <pre class="lang-none prettyprint-override"><code>1000   -&gt; 1.000
  23513  -&gt; 23.513
  999999 -&gt; 999.999
  </code></pre>
  
  <p>How can I do  this?</p>