JSFiddle - React, Tailwind, and code Playground

HTML

<button id="btn">
  Generate a number
</button>

<button id="rock">
  Click to see generated number
</button>

<div>
  <p>
  Generated number is: <span id="show-number">No number yet...</span>
  </p>
</div>

JavaScript

const btn = document.getElementById("btn")
const rock = document.getElementById("rock")

let randomNum

btn.onclick = function() {
	randomNum = Math.floor(Math.random() * (3-0)) + 0;
};

rock.onclick = function() {
   if (randomNum !== undefined) {
   	document.getElementById("show-number").innerHTML = randomNum;
   }
};