title: SASS division in @include not compiling
body: <p>I want to divide the grid-height with 2. But, it is not compiled to the expected value. Instead, it is compiled like this. </p>
  
  <p>This my scss code. I tried different combinations. None of them worked. Kindly point where the mistake is.</p>
  
  <pre><code>@mixin phone-size($width, $height) {
    @media screen and (min-height: $height) and (min-width: $width) {
      @content;
    }
  }
  
  @include phone-size(360, 480) {
  
    $img-height: 90px;
    $grid-height: #{$img-height * 3 + 6px};
  
    .text-wrapper {
      $two: 2px;
  
      bottom: $grid-height / 2;
      bottom: #{$grid-height / 2};
      bottom: $grid-height / 2px;
      bottom: #{$grid-height / (2)};
      bottom: $grid-height / $two;
      bottom: $grid-height / (2);
      bottom: ($grid-height / $two);
    }
  }
  </code></pre>
  
  <p>The compiled css code.</p>
  
  <pre><code>@media screen and (min-height: 480) and (min-width: 360) {
    .text-wrapper {
      bottom: 276px/2;
      bottom: 276px/2;
      bottom: 276px/2px;
      bottom: 276px/2;
      bottom: 276px/2px;
      bottom: 276px/2;
      bottom: 276px/2px;
    }
  }
  </code></pre>
  
  <p>I am using <a href="http://www.sassmeister.com/" rel="nofollow">http://www.sassmeister.com/</a> for testing. 
  Thanks in advance!</p>