PHP - suma de array bidimensional

<?php

$numeros = array ( array (1, 2, 3, 4),

				  array (5, 6, 7, 8, 9));

$fila = 4;

$columna = 5;

?>

$suma=array_sum(array_map('array_sum',$numeros));

echo "suma igual a ".$suma;

$suma=0;

foreach ($numeros as $array) {

    foreach($array as $valores) {

        $suma += $valores;

    }

}

echo "suma igual a ".$suma;

$suma=0;

foreach ($numeros as $array) {

   $suma += array_sum($array);

}

echo "suma igual a ".$suma;