use Math::BigInt ();

*gcd = \&Math::BigInt::bgcd;

sub embiggen {
   local $_ = @_ ? $_[0] : $_;
   return Math::BigInt->new($_);
}


my @a = ( 10, 20, 33, 45, 60 );
my @b = ( 2, 5, 10, 12, 16, 23, 45 );


# my %a = map { $_ => 1 } @a;
# my %b = map { $_ => 1 } @b;
#
# my @c = map embiggen,
#         grep { !$b{$_} }
#         @a;
#
# my @d = map embiggen,
#         map { Math::BigInt->new($_) } 
#         grep { !$a{$_} }
#         @b;

my @c = @a;
my @d = @b;

foreach my $c (@c) {
   foreach my $d (@d) {
      my $gcd = gcd($c, $d);
      $c /= $gcd;
      $d /= $gcd;
   }
}

@c = grep { $_ != 1 } @c;
@d = grep { $_ != 1 } @d;