sub one {
    my ($number) = @_;
    my $padded = sprintf("%09d",$number);
    $padded;
}

sub two {
    my ($number) = @_;
    my $padded = "000000000";
    my $length = length($number);
    substr($padded,(-$length),$length,$number);
    $padded;
}

print one(-6),"\n";     # -00000006
print two(-6),"\n";     # 0000000-6

print one(43/6),"\n";   # 000000007
print two(43/6),"\n";   # 7.16666666666667