$sayi1=$_POST['sayi1'];
$sayi2=$_POST['sayi2'];

if ($sayi1 > $sayi2) {
echo $sayi1.' > '.$sayi2;
}
elseif ($sayi2 > $sayi1) {
echo $sayi2.' > '.$sayi1;
}
else {
echo $sayi1.' = '.$sayi2;
}