title: Calculate and pass the sum of 2 variables values in a third
body: <p>I would like to calculate the width of 2 divs and pass the sum in a third, all values stocked in variables.</p>
  
  <p>HTML:</p>
  
  <pre><code>&lt;div id="value-a"&gt;&lt;/div&gt;
  &lt;div id="value-b"&gt;&lt;/div&gt;
  
  &lt;div id="value-c"&gt;&lt;/div&gt;
  </code></pre>
  
  <p>JQuery:</p>
  
  <pre><code>var value_a = $('#value-a').css('width');
  var value_b = $('#value-b').css('width');
  var value_c = (value_a + value_b);
  $('#value-c').css('width', value_c);
  </code></pre>
  
  <p>It look like i'm wrong with the syntax to make the operation... </p>
  
  <p>Many thanks in advance for your help.</p>