#!usr/bin/perl -w
use strict;

my @tests = (2,11,23,89,99);

foreach my $num (@tests)
{   
   my $units = $num % 10; #modulo is the remainder
   my $tens = ($num - $units)/10;
   printf "decimal=%02d BCD=%04b %04b\n", $num, $tens, $units;
}

__END__
decimal=02 BCD=0000 0010
decimal=11 BCD=0001 0001
decimal=23 BCD=0010 0011
decimal=89 BCD=1000 1001
decimal=99 BCD=1001 1001