JSFiddle - React, Tailwind, and code Playground

HTML

<label class='lbl'>120</label>
<label class='lbl'>250</label>
<label class='lbl'>342</label>
<label id="total"></label>

JavaScript

jQuery(document).ready(function($){
    var total = 0;
	$('.lbl').each(function() {
        var temp = $(this).html();
        total += parseFloat(temp);
    });
    $('#total').html(total);
});