Add Variables From Functions Using a Class

[unemployment]

I think I need to use $this, but I need to be able to add the two values returned from both of my functions.  How would I do that?

 

public function get_users_edge($uid)
{
$users_primary->get_users_primary_edge($uid);
$users_dynamic->get_users_dynamic_edge($uid);

echo $users_primary + $users_dynamic;
}