Trouble with date calculation

I am trying to do a date test on values coming back from an MySql database…here is my code…

while ($row = mysql_fetch_array($result))
{
$signUpDate = date(“m/d/Y”,strtotime($row[‘signupdate’]));
$lastLeadDate = date(“m/d/Y”,strtotime($row[‘lastleaddate’]));
$dateDiff = $signUpDate – $lastLeadDate;
$fullDays = floor($dateDiff/(60*60*24));
echo “<br/>”;
echo $signUpDate ;
echo “<br/>”;
echo $lastLeadDate;
echo “<br/>”;
echo $dateDiff;
echo “<br/>”;
echo $fullDays;

}

here is my results

06/08/2010
01/01/2011
5

I am not sure why I am getting the “5” which I assume is the diff in months

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