use Benchmark 'cmpthese';

$x = int (1_000_000 * rand 1_000_000);

cmpthese( -3, {
  mult => sub { $x =~ /(\d)*(\d)/  },
  bt_c => sub { $x =~ /(\d*)(\d)/  },
  bt   => sub { $x =~ /\d*(\d)/    },
  opt  => sub { $x =~ /(\d)$/      },
  mod  => sub { $x % 10            },
  chop => sub { my $x= $x; chop $x },
});