title: Displaying PHP result in the same page
body: <p>I want to add custom PHP to my wordpress site.
  I managed to do it but the result is displayed in another page and it is just simple text.</p>
  
  <p>I created simple calculator, and when user hits submit I want a div with the result to occur right below this calculator.</p>
  
  <p>What is the simple way to do it or where can I seek some advice? Couldn't find it on google.</p>
  
  <p>PS I am using wordpress themes so I added the action for the form as another file.</p>