JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
<div class="box">
    <div class="box_content">
        <div class="box_price">100</div>
    </div>
</div>
<div class="box">
    <div class="box_content">
        <div class="box_price">200</div>
    </div>
</div>
</div>

CSS

.content { display: none; float:right;padding:14px 20px;background:green; color:#fff}

JavaScript

var total =0;
$('.box > .box_content > .box_price').each(function(){
  total += parseInt($(this).text());
});
$('.container').append("<div class='sum'>Total : "+total+"</div>");
console.log(total);