How to calculate the amount of trade offers?

Question

1C-Bitrix

I count the sum of the availability of goods (according to the sum of the availability of all its tp)
code
<? foreach($arItem['OFFERS'] as $arOffer): ?>
<? $arOfferSum+=$arOffer['CATALOG_QUANTITY']; ?>
<? endforeach; ?>
as a result, the sum of the first one is calculated and then each product is added
how to calculate for each product separately, please tell me)

Answer 1

<? 
$arOfferSum = 0;
foreach($arItem['OFFERS'] as $arOffer){
  $arOfferSum += $arOffer['CATALOG_QUANTITY'];
}