JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="num1"/>+<input type="text" id="num2"/> =<label class="sum"></label>

JavaScript

$(document).ready(function() {
    $('#num1, #num2').keyup(function(){
        var num1 = parseInt($('#num1').val(),10) || 0;
        var num2 = parseInt($('#num2').val(),10) || 0;
        $('label.sum').text((num1 + num2)|| '')
    });
});