title: Numerical operation with absulute value in Django
body: <p>I tried to add three different absolute value in my template but I got always 0. I try to explain it:</p>
  
  <p><strong>My values:</strong></p>
  
  <pre><code>a=-7
  b=8
  c=10
  </code></pre>
  
  <p><strong>I tried this method with Django mathfilter:</strong></p>
  
  <pre><code>{{a|abs|add:b|abs|add:c|abs}}
  </code></pre>
  
  <p>I always got 0 because I think the mathfilter can't handle many abs value. Could anyone give me an advice which help me to do this operation? Thnak you in advance!</p>