p2@nereida:~/src/perl/testing$ cat precedence1.pl
my $n1 = 2;
my $n2 = 4;
print "$n1 plus $n2 is " . $n1 + $n2 . "\n";

##</code><code>##

pp2@nereida:~/src/perl/testing$ perl precedence1.pl
6

##</code><code>##

pp2@nereida:~/src/perl/testing$ cat precedence2.pl
use warnings;
my $n1 =2;
my $n2 = 4;
print "$n1 plus $n2 is " . $n1 + $n2 . "\n";

##</code><code>##

pp2@nereida:~/src/perl/testing$ perl precedence2.pl
Argument "2 plus 4 is 2" isn't numeric in addition (+) at precedence2.pl line 6.
6

##</code><code>##

pp2@nereida:~/src/perl/testing$ perl -MO=Deparse,-p precedence2.pl
use warnings;
use strict 'refs';
(my $n1 = 2);
(my $n2 = 4);
print(((("$n1 plus $n2 is " . $n1) + $n2) . "\n"));
precedence2.pl syntax OK

##</code><code>##

(((("$n1 plus $n2 is " . $n1) + $n2) . "\n"))