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

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

    while($result < $limit){
        $result = $i * $number;
        $sum += $result;
        echo $i . ' x ' . $number . ' = ' . $result . "\n";
        $i++;
    }
    if($result > $limit)
        $result = $result - ($i - 1) * $number;
}

echo $sum;