user@linux-mint ~/perl_practice $ more num_triple_by2.pl 
use strict;
use warnings;

my @tripled = map { $_ * 3 } my @list = (1..10);
print "\@list = @list\n\@tripled = @tripled\n";
my @div_by_two= grep { $_ % 2 == 0 } @tripled;
print "\@div_by_two = @div_by_two\n";

user@linux-mint ~/perl_practice $ perl num_triple_by2.pl 
@list = 1 2 3 4 5 6 7 8 9 10
@tripled = 3 6 9 12 15 18 21 24 27 30
@div_by_two = 6 12 18 24 30
user@linux-mint ~/perl_practice $