JSFiddle - React, Tailwind, and code Playground

HTML

<a href="" value="" class="add_row_count" id="hide">Add another row</a>
<table id='count' class="table table-bordered count" cellspacing="0" width="100%">
  <thead>
    <tr>
      <th style="text-align: center; width:180px"></th>
      <th style="text-align: center;">BEG</th>
      <th style="text-align: center;"> DEL</th>
      <th style="text-align: center;"> RET</th>
      <th style="text-align: center;"> EXC</th>
      <th style="text-align: center;"> P-OUT</th>
      <th style="text-align: center;"> SALES</th>
      <th style="text-align: center;"> END</th>
      <th style="text-align: center;"> ACTUAL COUNT</th>
      <th style="text-align: center;"> VARIANCE</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td style="text-align: center;">
        <input type="text" name="categ_name[]" class="calculate categ_name" value="" placeholder="Item Category" required>
      </td>
      <td style="text-align: center;">
        <input type="number" name="beg_count[]" class="calculate beg_count" value="" placeholder="BEG Count" required>
      </td>
      <td style="text-align: center;">
        <input type="number" name="del_count[]" class="calculate del_count" value="" placeholder="DEL Count" required>
      </td>
      <td style="text-align: center;">
        <input type="number" name="ret_count[]" class="calculate ret_count" value="" placeholder="RET Count" required>
      </td>
      <td style="text-align: center;">
        <input type="number" name="exc_count[]" class="calculate exc_count" value="" placeholder="EXC Count" required>
      </td>
      <td style="text-align: center;">
        <input type="number" name="pout_count[]" class="calculate pout_count" value="" placeholder="P-Out Count" required>
      </td>
      <td style="text-align: center;">
        <input type="number" name="sales_count[]" class="calculate sales_count" value="" placeholder="SALES Count" required>
      </td>
      <td style="text-align: center;">
        <input type="number"...

JavaScript

var $tbody = $('#count tbody');
$('.add_row_count').on('click', function() {
  event.preventDefault();
  var $row = $tbody.find('tr').eq(0).clone();
  $row.find('input').val('');
  var $newRow = $($row[0].outerHTML);
  $tbody.append($newRow);
});
$tbody.on('keyup', '.calculate', function() {
  var $tr = $(this).closest('tr');
  var end = $tr.find('.end_count').val();
  var ac = $tr.find('.actual_count').val();
  var total_variance = end - ac;
  $tr.find('.variance').val(total_variance);
});