my %hash=(A=>4, B=>5, C=>10, D=>2, E=>9);
my @zip = sort keys %hash;
do {
   my $f = shift @zip;
   for (@zip) {
	   my ($v1,$v2) = @hash{$f,$_};
	   print "$f($v1) * $_($v2) = ", $v1 * $v2, "\n";
   }
} while (@zip);