private function numberToNumerals($number, array $numerals)
    {
        $string = '';

        while ($number > 0) {
            foreach ($numerals as $n => $t) {
                if ($number >= $n) {
                    $string .= $t;
                    $number -= $n;
                    break;
                }
            }
        }

        return $string;
    }