$n1 = "\x1c-933"; ## hex( 1c ) == 28 == ^\ == Field separator
$n2 = "\x1c-1093"; 

print $n1 - $n2;;
Argument "^\-1093" isn't numeric in subtraction (-) at (eval 6) line 1
Argument "^\-933" isn't numeric in subtraction (-) at (eval 6) line 1
0