PHP Manual: Arithmetic

Arithmetic Operators

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

**Arithmetic Operators**
Example	Name	Result
`+$a`	Identity	Conversion of `$a` to int or float as appropriate.
`-$a`	Negation	Opposite of `$a`.
`$a + $b`	Addition	Sum of `$a` and `$b`.
`$a - $b`	Subtraction	Difference of `$a` and `$b`.
`$a * $b`	Multiplication	Product of `$a` and `$b`.
`$a / $b`	Division	Quotient of `$a` and `$b`.
`$a % $b`	Modulo	Remainder of `$a` divided by `$b`.
`$a ** $b`	Exponentiation	Result of raising `$a` to the `$b`'th power.

The division operator / returns a float value unless the two operands are int (or numeric strings which are type juggled to int) and the numerator is a multiple of the divisor, in which case an integer value will be returned. For integer division, see intdiv().

Operands of modulo are converted to int before processing. For floating-point modulo, see fmod().

The result of the modulo operator % has the same sign as the dividend — that is, the result of $a % $b will have the same sign as $a. For example:

Example #1 The Modulo Operator

<?php
var_dump(5 % 3);
var_dump(5 % -3);
var_dump(-5 % 3);
var_dump(-5 % -3);
?>

The above example will output:

int(2)
int(2)
int(-2)
int(-2)

Arithmetic Operators

See Also