i got this code but when i tested it i got no result:

if ($ARGV[0] eq "add")
{
$rtn = add($ARGV[1]);
print " The sum is $rtn";
}
elsif ($ARGV[0] eq "multiply")
{
$rtn = multiply($ARGV[1]);
print "ther prod is $rtn";
}
sub add{
my ($sum);
$sum=0;
foreach $_(@_) {
$sum +=$_;
}
return $sum;
}
sub multiply {
my ($multiply);
$product=0;
foreach $_(@_) {
$product+=$_;
}
return $multiply:
}

am i doing it right?