my %table = (
	'a' => '10',
	'b' => '11',
	'c' => '12',
	'd' => '13',
	'e' => '14',
	'f' => '15',
);

my @numbers = ('a0', '11', 'ff', '9084fe', '10');

foreach my $trial (@numbers) {
	my @digits = split //, $trial;
	my $result = 0;
	foreach my $digit (@digits) {
		$result *= 16;
		$result += 
			$digit =~ /\d/ ? 
				$digit :
				$table{lc($digit)};
	}
	print "$trial is actually $result\n";
}