i made some modifications to your code and it will now basically do what you need : 
#!/user/bin/perl -w
use strict;
use warnings;

my ($add,$first_number,$second_number,$subtract,$times,$divide);

print "Welcome to the mathq program\n\n";
while(1){
    print "Enter a number : ";
    $first_number = <STDIN>;
    chomp($first_number);
    if ($first_number eq "q") {
        die "Goodbye\n";
    }    
    else {
        print "Enter a second number : ";
        $second_number = <STDIN>;
        print "\n\n";
        chomp ($second_number);
        $add = $first_number + $second_number;
        $subtract = $first_number - $second_number;
        $times = $first_number * $second_number;
        print "$first_number + $second_number =  $add\n";
        print "$first_number - $second_number = $subtract\n";
        print "$first_number x $second_number = $times\n";        
        if($second_number!=0){
            $divide = $first_number / $second_number;
            print "$first_number / $second_number = $divide\n";
        }
        print "\n\n";
    }
}

[download]

but you'll still have to filter illegal inputs...

In reply to Re: Homework: simple calculator by m0ve
in thread Homework: simple calculator by R4j4

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