JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" class="input value1">
<input type="text" class="input value2 ">
<input type="text" disabled="disabled" id="result">

JavaScript

$(document).ready(function(){
$('input[type="text"]').keyup(function () {
  var val1 = parseInt($('.value1').val());
  var val2 = parseInt($('.value2').val());
          var sum = val1+val2;
          $("input#result").val(sum);
});
});