How can i change this code for multiplication? : i have this code and i am using for addition of inputs. How can i change this code for multiplication?

    		function sumIt() {
		  var total = 0, val;
		  $('.inst_amount').each(function() {
			val = $(this).val();
			val = isNaN(val) || $.trim(val) === "" ? 0 : parseFloat(val);
			total += val;
		  });
		  $('#total_price').html(Math.round(total));
		  $('#total_amount').val(Math.round(total));
		}

		$(function() {

		  $("#add").on("click", function() {
			$("#container input").last()
			  .before($("<input />").prop("class","inst_amount").val(0))
			  .before("<br/>");
			sumIt();  
		  });

		  $(document).on('input', '.inst_amount', sumIt);
		  sumIt() // run when loading
		});