JSFiddle - React, Tailwind, and code Playground

HTML

<span class='hi'> 100 </span>

CSS

* {
  box-sizing: inherit;
}

html {
  box-sizing: border-box;
}
body {
  margin: 0;
}

JavaScript

$(document).ready(function(){
        $(".hi").text(+$(".hi").text() + 100);
    });