JSFiddle - React, Tailwind, and code Playground

HTML

<div id="one">1</div>

<div id="two">5</div>

<div id="total">0</div>

<input id="btn-calculate" type="button" value="Calculate" />

JavaScript

$('#one').click(function(){
$("#total").text(
    parseFloat($(this).text()) + 
    parseFloat($("#two").text())
);
});