Arithmetic Operators

Remember basic arithmetic from school? These work just like those.

Table 15-2. Arithmetic Operators

ExampleNameResult
-$aNegationOpposite of $a.
$a + $bAdditionSum of $a and $b.
$a - $bSubtractionDifference of $a and $b.
$a * $bMultiplicationProduct of $a and $b.
$a / $bDivisionQuotient of $a and $b.
$a % $bModulusRemainder of $a divided by $b.

The division operator ("/") returns a float value anytime, even if the two operands are integers (or strings that get converted to integers).

Note: Remainder $a % $b is negative for negative $a.

See also the manual page on Math functions.