title: calc not working ie 11
body: <p>After researching I confirmed that calc should work for ie8+ but it is not working for me.</p>
  
  <p>Here is a JS fiddle I made:</p>
  
  <p><a href="http://jsfiddle.net/75tzyLoo/" rel="noreferrer">http://jsfiddle.net/75tzyLoo/</a></p>
  
  <p>here is the code:
  HTML:</p>
  
  <pre><code>&lt;div id="outer"&gt;
      &lt;div id="inner"&gt;
  
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>CSS:</p>
  
  <pre><code>#outer{
      width:400px;
      background-color:black;
      height:200px;
  }
  #inner{
      width:calc(80%-100px);
      width:expression(80%-100px);
      background-color:red;
      height:100%;
  
  }
  </code></pre>
  
  <p>and here is the output I see: <img src="https://i.stack.imgur.com/hUkHF.jpg" alt="JS Fiddle output for calc not working"></p>
  
  <p>What am I doing wrong?</p>