• Numeric operations apply a numeric context
• Undefined values are treated as zero
• Scalars are evaluated as numbers
• Strings are converted to their numeric value automatically
• Non-number strings are converted to zero
• Arrays are evaluated as their length

        my $number;
        my $string;                  # Zero in numeric context
        $number = $string + 17;
        print "Number is $number.\n";

        $string = "5.2";             # 5.2 in numeric context
        $number = $string + 17;
        print "Number is $number.\n";

        $string = "five";            # Zero in numeric context
        $number = $string + 17;
        print "Number is $number.\n";
      

        Number is 17.
        Number is 22.2.
        Number is 17.