<?php
$numbers = array(4, 7);
$limit = 1000;
$sum = 0;

foreach($numbers as $number){
    $i = 1;
    $stop = 0;

    while($stop < $limit){

        $sum += ($result = ++$i * $number);

        echo $i . ' x ' . $number . ' = ' . $result . '<br />';

        $stop = ($i + 1) * $number;
    }
}

echo '<strong>Le som is: ' . number_format($sum, 0, ',', '.') . '</strong>';