How to Add values from checkboxes

How to Add values from checkboxes

    Hello Everyone,
    I am trying to sum the values from the selected checkboxes ... But so far what i am getting is like 2,3...what i want is 5....Can anybody help me out to get this logic please. Thanks!!!!

    2. <html>
    3. <head>
    4.   <title>jQuery With Example</title>
    5.   <script src="http://code.jquery.com/jquery-1.9.1.js" 

    7. type="text/javascript"></script>
    8.   <script type="text/javascript">
    9.     $(function () {
    10.       $('.btnGetSelectedValue').click( function(){
    11.         var chkId = '';
    12.         $('.chkNumber:checked').each(function() {
    13.           chkId += $(this).val() + "+";
    14.         });
    15.    /*     chkId =  chkId.slice(0,-1); */
    16.         alert(chkId);
    17.       });

    19.      

    21.     });
    22.   </script>
    23. </head>
    24. <body>
    25.   <div>
    26.     <input type="checkbox" class="chkNumber" value="1" />One<br />
    27.     <input type="checkbox" class="chkNumber" value="2" />Two<br />
    28.     <input type="checkbox" class="chkNumber" value="3" />Three<br />
    29.     <input type="checkbox" class="chkNumber" value="4" />Four<br />
    30.     <input type="checkbox" class="chkNumber" value="5" />Five<br /><br 

    32. />
    33.   </div>
    34.   <button type="button" 

    36. class="btnGetSelectedValue">GetSelectedValue</button><br />

    38. </body>
    39. </html>