Add quantity and price to a checkbox with a initial value

Please, i need help for create a simple form which takes into account a price and a quantity. There is also an initial value. Thank you.

HTML:

<input type="number" min="0" max="5"  value="1" onclick="total(this.form);"/>
<input type='checkbox' value='10' />10
<div id='total'></div>

JAVASCRIPT:

var init_price = 200;
$('#total').html(init_price);
var tot = 0;
$('input:checkbox').change(function(){
    if($(this).is(':checked')){
        tot = Number($('#total').html()) + Number($(this).val());
    } else {
        tot = Number($('#total').html()) - Number($(this).val());
    }

    $('#total').html(tot);
});

JSFIDDLE