G'day mrguy123,

"Solved -thanks for the help. Am now trying to discover how "safe" using given/when is (as of Perl 5.18, given/when has been marked experimental and issues warnings because it may undergo major changes in a future version of Perl)"

You can avoid the (experimental) given/when/.../default construct by using a (non-experimental) for/if/elsif/.../else construct. Here's an example for your specific range comparison:

$ perl -Mstrict -Mwarnings -E '
    my $re_2_5 = qr{^@{[join "|", 2 .. 5]}$};
    my $re_6_10 = qr{^@{[join "|", 6 .. 10]}$};

    for my $x (4 .. 7, 11) {
        for ($x) {
            if (/$re_2_5/) { say "$_ in 2-5 range" }
            elsif (/$re_6_10/) { say "$_ in 6-10 range" }
            else { say "$_ not in range" }
        }
    }
'
4 in 2-5 range
5 in 2-5 range
6 in 6-10 range
7 in 6-10 range
11 not in range
[download]

There's lots of other ways to achieve this. Here's one using nested ternary operators:

$ perl -Mstrict -Mwarnings -E '
    my $re_2_5 = qr{^@{[join "|", 2 .. 5]}$};
    my $re_6_10 = qr{^@{[join "|", 6 .. 10]}$};

    for my $x (4 .. 7, 11) {
        for ($x) {
            say 
                  /$re_2_5/  ? "$_ in 2-5 range"
                : /$re_6_10/ ? "$_ in 6-10 range"
                :              "$_ not in range"
        }
    }
'
4 in 2-5 range
5 in 2-5 range
6 in 6-10 range
7 in 6-10 range
11 not in range
[download]

See also perlsyn - Basic BLOCKs which has other alternatives.