http://www.perlmonks.org?node_id=622704
monkfan has asked for the wisdom of the Perl Monks concerning the following question:

Hi,
I was trying to substract these two values:
my $n1 = '-933'; my $n2 = '-1039'; my $dif = $n1 - $n2;
In print Dumper for "n1" and "n2" looks like this:
$VAR1 = '-933'; $VAR1 = '-1039';
But how come when I substracted them, they give:
Argument "^\-933" isn't numeric in subtraction (-) at mycode.pl line 1 +15. Argument "^\-1039" isn't numeric in subtraction (-) at mycode.pl line +115.
Where the "$dif" value is printed as 0. How can I overcome this problem?

update: Here is some additional context. Earlier, $n1 and $n2 was obtained from this step:
my $some_string = "0,-933"; my ($id1,$n1) = split(",",$some_string);
And my Perl version is:
This is perl, v5.8.5 built for i386-linux-thread-multi

Regards,
Edward