title: Purpose of 62.5% font-size in elastic layouts
body: <p>There existing a practice to set body font to 62.5 %, so 1 em would be equal to 10 px. Also it is known that this method has some drawbacks.</p>
  <pre><code>body {
    font-size: 62.5%;
  }
  </code></pre>
  <p>As stated in several articles,</p>
  <p>Quote form <a href="https://csswizardry.com/2011/05/font-sizing-with-rem-could-be-avoided/" rel="nofollow noreferrer">1st article</a>:</p>
  <blockquote>
  <p>The 62.5% trick is a common one, and does have its uses in two circumstances:</p>
  <ul>
  <li><p>You want simpler maths, for example if you are building an elastic layout (width:30em; == width:300px;)</p>
  </li>
  <li><p>&lt;...&gt;</p>
  </li>
  </ul>
  </blockquote>
  <p>Quote from <a href="http://www.exsertus.be/2013/06/rem-ems-and-px-when-size-does-matter/" rel="nofollow noreferrer">another article</a>:</p>
  <blockquote>
  <p>The 62.5% Hack is a common one and has its uses and drawbacks.</p>
  <p>I only recommend using it if you want simpler maths, for example if you are building an elastic layout.</p>
  </blockquote>
  <p>I want to know how exactly 62.5 %-trick helps in building elastic layouts. Some simple examples?</p>