Possible Duplicate:
PHP negatives keep adding

I have this code here....

$remaining = 0;
foreach($array as $value=>$row){
        $remaining = $remaining + $row['remainingbalance'];
}

What its doing is that it is going through all the remaining balances in the array which are -51.75 and -17.85 with the code above I get -69.60 which is correct. But I am wondering how when its two negatives if they could subtract? Is that possible?

I tried this

$remaining = 0;
foreach($clientArrayInvoice as $value=>$row){
        $remaining = $remaining + abs($row['remainingbalance']);
}

but it gives me 69.60 without the negative.

Anyone got any ideas?

my goal is to take -51.75 and -17.85 and come up with -33.90 only when its a negative to do subtract. otherwise add