my $sort_by_numeric_value = sub {
    my $hash = shift;
    [ sort {$hash->{$b} <=> $hash->{$a}} keys %$hash ];
};

tie my %sorted_ages, 'Tie::Hash::Sorted',
                     'Hash' => \ %ages,
                     'Sort_Routine' => $sort_by_numeric_value;

for my $name ( keys %sorted_ages ) {
   print "$name is $sorted_ages{$name} years old.\n";
}

##</code><code>##

sub by_numeric_value {
    $ages{$b} <=> $ages{$a}
}

for my $name (sort by_numeric_value keys %ages) {
    print "$name is $ages{$name} years old.\n";
}