To calculate the total of all numeric and multi-numeric inputs when any are changed:

<script type="text/javascript" charset="utf-8">
$(document).ready(function() {
// Listener on all numeric and multi-numeric inputs
$('.numeric-multi input.text, .numeric input.text').change(function(){
var inputTotal = 0;
$('.numeric-multi input.text, .numeric input.text').each(function(){
inputTotal = inputTotal + Number($(this).val());
});
alert (inputTotal);
});
});
</script>

To calculate the total of all numeric and multi-numeric inputs when next/submit is clicked:

<script type="text/javascript" charset="utf-8">
$(document).ready(function() {
// Interrupt the Next/Submit function
$('form#limesurvey').submit(function(){
// Override the built-in "disable navigation buttons" feature
$('#moveprevbtn, #movenextbtn, #movesubmitbtn').attr('disabled', '');
var inputTotal = 0;
$('.numeric-multi input.text, .numeric input.text').each(function(){
inputTotal = inputTotal + Number($(this).val());
});
alert (inputTotal);
return true;
});
});
</script>