#!/usr/bin/perl -w

use strict;

my @a = (1,2,3);
my @b = (4,5,6);
my @c = (7,8,9,0);

my @array = (@a, @b, @c);
my $size = @array;
# $size will be 10
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If it is an array of array refs, you could do:

#!/usr/bin/perl -w

use strict;

my @a = (1,2,3);
my @b = (4,5,6);
my @c = (7,8,9,0);

my @array = (\@a, \@b, \@c);
my $i;
for (@array) {
        $i += @$_;
}
# $i will be 10, scalar @array will be 3
[download]

If it is another scenario, you should now be able to figure out your solution.

Cheers,
KM