my %hash = map { $numbers[$_] => $signs[$_]} 0 .. $#numbers;

while (($key, $value) = each (%hash))  {

      if (@new_numbers)   {
              for (my $i=0; $i<@new_numbers; $i++)   {
                     if ($key == $new_numbers[$i])   {
                             print "$value \t $new_numbers[$i]";  # this prints the sign and the number it matches to
                     }
              }
      }