JSFiddle - React, Tailwind, and code Playground

HTML

<table>
<tr>
<td class="timesheet2"><input type="text" name="daymon" id="monday"></td>
<td class="timesheet2"><input type="text" name="daytue" id="tuesday"></td>
<td class="timesheet2"><input type="text" name="daywed" id="wednesday"></td>
<td class="timesheet2"><input type="text" name="daythurs" id="thursday"></td>
<td class="timesheet2"><input type="text" name="dayfri" id="friday"></td>
<td class="timesheet2"><input type="text" name="daysat" id="saturday"></td>
<td class="timesheet2"><input type="text" name="daysun" id="sunday"></td>
<td class="timesheet"><div id="total_amount"></div></td>
</tr>
</table>

JavaScript

$("[id$=day]").change(function() {
    var total = 0;     
    $('.timesheet2 input').each(function() {
        total = total + Number( $(this).val() );
    });
    $('div#total_amount').html(total); 
});