Secret Number

Score: 66.00 (fail)

#!/usr/bin/perl -l
$_=pop;do{print;s/(.)(?=(.))/($1+$2-1)%9+1/ge;chop}while length

Score: 74.00 (pass)

#!/usr/bin/perl -l
($_,@a)=(pop,0..9,1..9);do{print;s/(.)(?=(.))/$a[$1+$2]/ge;chop}while$_