Call Contoller php function by View html

My question regarding codeigniter

I want to call a 'add' method in the 'calc.php' (controller class) by using calc_view (view class)

calc.php - controller class

   <? php 
   function add(){

        return ($user['askcount'] * 1) 
               + ($user['anzcount'] * 10) 
               + ($user['voteupcount'] * 5) 
               - ($user['votedowncount'] * 2)); 
   }

want to get input of "localhost/index.php/calc/add" in calc_view

     <div id = 'addresult'> ......... </div>