JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
	<h1>jQuery live Try</h1>
	<form>
		<input type="text" placeholder="Number 1" class="num1 key">
		<input type="text" placeholder="Number 2" class="num2 key">
		<br><br>
		Sum: <input type="text" class="sum" readonly="readonly"><br><br><br>
	</form>
</div>

JavaScript

$(document).ready(function(){
			$(".sum").val("0");
			$(".key").val("");
			
			function calc(){
			var $num1=parseInt($(".num1").val(), 10) || 0;
			var $num2=parseInt($(".num2").val(), 10) || 0;
			$(".sum").val($num1+$num2);
		}
		$(".key").keyup(function(){
			calc();
		});
});