title: Unexpected result subtracting decimals in ruby
body: <p>I'm doing a simple subtraction between 2 decimals in ruby, but am getting a suprisingly odd result.  If I run the following in IRB, I would have expected to get 0.011.  I realize I can do (0.942 - 0.931).round(3) to get the answer I'm expecting, but am wondering why ruby returns the result it does.</p>
  
  <pre><code> 1.9.3-p551 :004 &gt; (0.942 - 0.931)
   =&gt; 0.010999999999999899
  </code></pre>