JSFiddle - React, Tailwind, and code Playground

HTML

<span class='pups'>100</span>
<span class='pups'>200</span>
<span class='pups'>300</span>
<span class='pups'>3300</span>
<span class='pups'>9993300</span>

CSS

span {
  display: block;
}

JavaScript

$('.pups').each(function() {
  this.innerHTML = (parseInt(this.textContent) * 10)
    .toString()
    .split('')
    .reverse()
    .map((char, i) => char + (i % 3 ? '' : ' '))
    .reverse()
    .join('')
})