JSFiddle - React, Tailwind, and code Playground

HTML

9.9 - 9 = <input type="text" size=30/>

<h1>WAT</h1>

parseFloat((9.9 - 9).toFixed(2)) = <input type="text" size=30/>

<h1>le sigh</h1>

JavaScript

document.getElementsByTagName('input')[0].value = (9.9 - 9);

document.getElementsByTagName('input')[1].value = parseFloat((9.9 - 9).toFixed(2));