JSFiddle - React, Tailwind, and code Playground

HTML

<span id='number'>0.2547</span>
<input tyoe='text' id='test'/>
<input type='text' id='result'/>

JavaScript

$("#test").keyup(function(){
    
   var number = $("#number").text();
   var current = $(this).val();
   
   var total = number*current;
   
   $("#result").val(total);
    
});