sub damm {
    my(@digits) = split '', @_[0];
    my @tbl =([< 0 3 1 7 5 9 8 6 4 2 >],
              [< 7 0 9 2 1 5 4 8 6 3 >],
              [< 4 2 0 6 8 7 1 3 5 9 >],
              [< 1 7 5 0 9 8 3 4 2 6 >],
              [< 6 1 2 3 0 4 5 9 7 8 >],
              [< 3 6 7 4 2 0 9 5 8 1 >],
              [< 5 8 6 9 7 2 0 1 3 4 >],
              [< 8 9 4 5 3 6 2 0 1 7 >],
              [< 9 4 3 8 6 1 7 2 0 5 >],
              [< 2 5 8 1 4 3 6 7 9 0 >]
              );
    my $row = 0;
    for my $col (@digits) { $row = $tbl[$row][$col] }
    not $row
}

for (5724, 5727, 112946) {
    print "$_:\tChecksum digit @{[damm($_) ? '' : 'in']}correct.\n"
}