$amount = 128.40;
$arub = 128;
$acop = 40;
$num = 128.40;
$arr = explode(".", $num );
list( $arub, $acop ) = $arr ;
$acop *= 10;
echo "$arub : $acop";
$num = 128.40;
$arub = floor( $num );
$acop = floor( ( $num - $arub ) * 100 );
echo "$arub : $acop";