JSFiddle - React, Tailwind, and code Playground

HTML

<div id="number">123</div>

JavaScript

setInterval(function(){
    random = (Math.floor((Math.random()*15)+1));
    var plusOrMinus = Math.random() < 0.5 ? -1 : 1;
    random = random * plusOrMinus; 
    currentnumber = document.getElementById('number');

    document.getElementById('number').innerHTML =  parseInt(currentnumber.innerHTML) + random;

 }, 1000);