Юсуф,
... изменить значение в предпоследних ячейках, чтобы увидеть результат
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
tr td:nth-last-child(2), #out{
border: 3px solid #0000FF;
}
</style>
</head>
<body>
<table><tbody>
</tbody></table>
<output id="out"></output>
<script>
const tbody = document.querySelector('table tbody');
let html = "";
for (let NumPodstr = 0; NumPodstr < 3; NumPodstr++) {
html +='<tr id="rrr"><td id="SmetaTableNum" class=""></td>'+
'<td id="SmetaTableName"><input type="text" name="referal[]" id="referal'+NumPodstr+'" value="" class="who" autocomplete="off" />'+
'<div id="search_result" class="search_result'+NumPodstr+'"></div></td>'+
'<td id="SmetaTableEd"><select name="Ed[]"><option value="шт.">шт.</option><option value="м²">м²</option><option value="м³">м³</option><option value="упак.">упак.</option>'+
'<option value="метр">метр</option><option value="м.п.">м.п.</option><option value="комп.">комп.</option><option value="смена">смена</option></select></td>'+
'<td id="SmetaTableObem"><input type="number" name="Obem[]" id="Obem'+NumPodstr+'" type="text" value="" /></td>'+
'<td id="SmetaTableMat"><input type="number" name="Material[]" id="Material'+NumPodstr+'" value="" /></td>'+
'<td id="SmetaTableSMR"><input type="number" name="SMR[]" id="SMR'+NumPodstr+'" /></td>'+
'<td id="SmetaTableItog"><input type="number" name="Itog[]" id="Itog'+NumPodstr+'" value="" /></td>'+
'<td id="Minus"><button type="button" id="StrocaMinus">-</button></td></tr>';
}
tbody.innerHTML = html;
tbody.addEventListener( "input" , function(event) {
event.preventDefault();
const itog = document.querySelectorAll('table tbody tr [name="Itog[]"]');
let sum = 0;
for(const {value} of itog) sum += Number(value);
out.textContent = sum;
});
</script>
</body>
</html>