JSFiddle - React, Tailwind, and code Playground

HTML

<div class="numberBox">
Number1
</div>
<div class="numberBox">
Number2
</div>
<div class="numberBox">
Number3
</div>

JavaScript

function generateRandomNumbers() {
	return Math.floor(Math.random() * 999999) + 10000;
}

var x = document.getElementsByClassName("numberBox");

for (var i = 0; i < x.length; i++) {
    x[i].innerHTML= '';
    x[i].innerHTML= "<div class='loader'></div>"
}

for (let i = 0; i < x.length; i++) {
    setTimeout(function() {
      x[i].innerHTML= '';
  		x[i].innerHTML = generateRandomNumbers();
    }, 3000 * i);
}