Hi robert44444uk,

Just to further add to what the Monks above have imparted - ever heard of recursion?

#! perl -slw
use strict;
sub count_id (\@\@); # "count indivisible dividends" fnc prototype
sub count_id (\@\@) {
    my ($divisors,$range) = (shift,shift);
    return 0 unless @$range && @$divisors; # check terminal condition

    # apply the $divisors to the dividend for this recursive call
    my ($aggregate,$dividend) = (0,pop @$range);
    for (@$divisors) { return count_id(@$divisors,@$range) if !($divid
+end % $_); }
    return 1 + count_id(@$divisors,@$range);
}
my @divisors = (13,17,19); my @range = (1..2310);
print "Number of indivisible items: ",count_id(@divisors,@range),"\n";
__END__
[download]

Thank you Shadowsong, this is also a very useful piece of code, and I will play with it for sure, when I get the chance.