JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" class="one">

<input type="text" class="two">

<input type="text" class="three">

JavaScript

$('.two').blur(function() {
			var hunder='100';
      var one=$('.one').val();
      var two=$('.two').val();
      var add=parseFloat(one) + parseFloat(two);
      var over = hunder - add;
      $('.three').val(over);
});