JSFiddle - React, Tailwind, and code Playground

HTML

<table id="math-table">
        <tr>
               <td><input type="text" id="A1" name="A" value=""></td>
               <td><input type="text" id="B1" name="B" value=""></td>
               <td><input type="text" id="C1" name="C" readonly="readonly" tabIndex="-1" value=""></td>
          </tr>
    </table>
<div id="button">add row +</div>

CSS

.red
{
    background-color:red;
}
.green
{
    background-color:green;
}
.blue
{
    background-color:blue;
}

JavaScript

$("#math-table input").live("keyup", function(){
 var id = this.id.match(/\d+/);
    var percent=Math.round (($("#A"+id).val() / $("#B"+id).val()) * 100);
   $("#C"+id).val( percent + "%"  );

   $('#A'+id).attr('value', $('#A'+id).val());  
   $('#B'+id).attr('value', $('#B'+id).val());  
   $('#C'+id).attr('value', $('#C'+id).val());  
    if(percent>0 && percent<34)
        $('#C'+id).removeClass().addClass('red');
    if(percent>33 && percent<67)
        $('#C'+id).removeClass().addClass('green');
    if(percent>67)
        $('#C'+id).removeClass().addClass('blue');
        
});

var uniqueIds = $("#math-table tr").length;
$("#button").click(function(){
var $thisRow = $(this).closest("tr"),
    $clone = $thisRow.removeClass().clone(),             // Clone row
    $inputs = $clone.find("input").val("").removeClass();// Reset values, return all inputs
uniqueIds++; //Increment ID
$inputs[0].id = "A" + uniqueIds;
$inputs[1].id = "B" + uniqueIds;
$inputs[2].id = "C" + uniqueIds;

    
//$inputs.eq(0).focus();                     
$thisRow.after($clone);                    
});