elsif($length == 2) {
        $num = (substr($num, 0, 1) + 1) . ('0'x($length-1));
}

##</code><code>##

elsif($length == 2) {
        $num = (substr($num, 0, 1) + 1) . '0';
}

##</code><code>##

elseif($length == 2){
    $num = int($num/10) * 10;
}