title: Addition is not working in JavaScript
body: <p>I am trying to learn Javascript. Here I am confused with the following code.</p>
  
  <p><a href="http://rendera.heroku.com/usercode/eae2b0f40cf503b36ee346f5c511b0e29fc82f9e" rel="noreferrer">http://rendera.heroku.com/usercode/eae2b0f40cf503b36ee346f5c511b0e29fc82f9e</a></p>
  
  <p>When I put <code>x+y</code> in the function it is going wrong. For example <code>2+2=22</code>, <code>5+7=57</code></p>
  
  <p>But <code>/</code>, <code>*</code>, <code>-</code> are working. Why is <code>+</code> not working? Please help me. Thanks a lot in advance</p>