title: Ratio of two variables in Sass
body: <p>I am trying to scale a value based on the ratio of two variables:</p>
  <pre><code>$w: 500px;
  $a: 1px;
  $b: 2px;
  $result: calc(#{$w} * #{$a}/#{$b});
  </code></pre>
  <p>I tried doing <code>calc(#{$w} * math.div(#{$a},#{$b}));</code> instead. To my surprise, I could not find any previous post on the topic.</p>
  <p>So, how do I achieve this?</p>