JSFiddle - React, Tailwind, and code Playground

HTML

<pre id="output"></pre>

JavaScript

function multiply (a, b) {
   exp = b.toString().length - 2;
   function makeInt (num) {
       return num * Math.pow(10, exp);
   }
   function makeFloat(num) {
       return num / Math.pow(100, exp);
   }
   return makeFloat(makeInt(a) * makeInt(b));
} 

var result = multiply(38.8,3)

document.getElementById('output').innerHTML = result;