If you mean you want to test if the 2's place is set, you can use bitwise operators (see Bitwise And and Bitwise Or and Exclusive Or in perlop). Something like

#!/usr/bin/perl
use strict;
use warnings;


for my $value (1, 2, 3, 4, 5, 6, 7, 8) {
    print "$value: ";
    if ($value & 0x2) {
        print "yes\n";
    } else {
        print "no\n";
    }
}
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This was recently discussed in Bit operation.