JavaScript Arithmetic

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JavaScript Arithmetic Operators

Arithmetic operators perform arithmetic on numbers (literals or variables).

Operator	Description
+	Addition
-	Subtraction
*	Multiplication
/	Division
%	Modulus (Remainder)
++	Increment
--	Decrement

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Arithmetic Operations

A typical arithmetic operation operates on two numbers.

The two numbers can be literals:

Example

var x = 100 + 50;

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or variables:

Example

var x = a + b;

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or expressions:

Example

var x = (100 + 50) * a;

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Operators and Operands

The numbers (in an arithmetic operation) are called operands.

The operation (to be performed between the two operands) is defined by an operator.

Operand	Operator	Operand
100	+	50

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Adding

The addition operator (+) adds numbers:

Example

var x = 5;
var y = 2;
var z = x + y;

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Subtracting

The subtraction operator (-) subtracts numbers.

Example

var x = 5;
var y = 2;
var z = x - y;

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Multiplying

The multiplication operator (*) multiplies numbers.

Example

var x = 5;
var y = 2;
var z = x * y;

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Dividing

The division operator (/) divides numbers.

Example

var x = 5;
var y = 2;
var z = x / y;

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Remainder

The modulus operator (%) returns the division remainder.

Example

var x = 5;
var y = 2;
var z = x % y;

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In arithmetic, the division of two integers produces a quotient and a remainder.
In mathematics, the result of a modulo operation is the remainder of an arithmetic division.

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Incrementing

The increment operator (++) increments numbers.

Example

var x = 5;
x++;
var z = x;

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Decrementing

The decrement operator (--) decrements numbers.

Example

var x = 5;
x--;
var z = x;

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Operator Precedence

Operator precedence describes the order in which operations are performed in an arithmetic expression.

Example

var x = 100 + 50 * 3;

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Is the result of example above the same as 150 * 3, or is it the same as 100 + 150?

Is the addition or the multiplication done first?

As in traditional school mathematics, the multiplication is done first.

Multiplication (*) and division (/) have higher precedence than addition (+) and subtraction (-).

And (as in school mathematics) the precedence can be changed by using parentheses:

Example

var x = (100 + 50) * 3;

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When using parentheses, the operations inside the parentheses are computed first.

When many operations have the same precedence (like addition and subtraction), they are computed from left to right:

Example

var x = 100 + 50 - 3;

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JavaScript Operator Precedence Values

Pale red entries indicates ECMAScript 2015 (ES6) or higher.

Value	Operator	Description	Example
20	( )	Expression grouping	(3 + 4)
19	.	Member	person.name
19	[]	Member	person["name"]
19	()	Function call	myFunction()
19	new	Create	new Date()
17	++	Postfix Increment	i++
17	--	Postfix Decrement	i--
16	++	Prefix Increment	++i
16	--	Prefix Decrement	--i
16	!	Logical not	!(x==y)
16	typeof	Type	typeof x
15	**	Exponentiation (ES7)	10 ** 2
14	*	Multiplication	10 * 5
14	/	Division	10 / 5
14	%	Division Remainder	10 % 5
13	+	Addition	10 + 5
13	-	Subtraction	10 - 5
12	<<	Shift left	x << 2
12	>>	Shift right	x >> 2
12	>>>	Shift right (unsigned)	x >>> 2
11	<	Less than	x < y
11	<=	Less than or equal	x <= y
11	>	Greater than	x > y
11	>=	Greater than or equal	x >= y
11	in	Property in Object	"PI" in Math
11	instanceof	Instance of Object	instanceof Array
10	==	Equal	x == y
10	===	Strict equal	x === y
10	!=	Unequal	x != y
10	!==	Strict unequal	x !== y
9	&	Bitwise AND	x & y
8	^	Bitwise XOR	x ^ y
7	|	Bitwise OR	x | y
6	&&	Logical AND	x && y
5	||	Logical OR	x || y
4	? :	Condition	? "Yes" : "No"
3	+=	Assignment	x += y
3	+=	Assignment	x += y
3	-=	Assignment	x -= y
3	*=	Assignment	x *= y
3	%=	Assignment	x %= y
3	<<=	Assignment	x <<= y
3	>>=	Assignment	x >>= y
3	>>>=	Assignment	x >>>= y
3	&=	Assignment	x &= y
3	^=	Assignment	x ^= y
3	|=	Assignment	x |= y
2	yield	Pause Function	yield x
1	,	Comma	5 , 6

Expressions in parentheses are fully computed before the value is used in the rest of the expression.