$k = 1;
foreach ($news as $new) {
if ($k === 3) {
} else if ($k === 4) {
} else {}
$k++;
}
<div class="item" id="<?=$this->GetEditAreaId($arItem['ID']);?>" style="width:<?=floor(100/intval($arParams["COLS_NUMBER"]));?>%;">
<div class="item col-md-<?=$arParams["COLS_NUMBER"]?>"