JSFiddle - React, Tailwind, and code Playground

HTML

<div class="package">
<input type="number" min="1" name="count" class="count" value="1">
<div class="price">320</div>
<span class="old-price">320</span>
</div>

JavaScript

$(document).ready(function() {
  function change($tr, val) {
    var $input = $tr.find('.count');
    var count = parseInt($input.val()) + val;
    count = count < 1 ? 1 : count;
    $input.val(count);
    var $price = $tr.find('.price');
    $price.text(count * parseInt($('.old-price').text()));
  }
  $('.count').on("input", function() {
    var $price = $(this).closest('.package').find('.price');
    $price.text(this.value * parseInt($('.old-price').text())); 
  });
});