title: How to convert X months to Y days in Rails in one step?
body: <p>I have a configuration value stored as <code>3.months</code>, and another value returning from a calculation as <code>7.days</code>. </p>
  
  <p>I need to find their difference. What is the easiest &amp; Railsiest way to normalise them so that I can subtract <code>7.days</code> from <code>3.months</code>? I can turn .months into days by using .to_i &amp; multiplying by seconds-in-a-day, but it feels pretty long-winded to have to calculate from months to seconds to days like this:</p>
  
  <pre><code>  x = (3.months.to_i/86400).days
    =&gt; 90 days
    x - 7.days
    =&gt; 83 days
  </code></pre>
  
  <p>Is there a snappier way?</p>