JS Arithmetic

JavaScript Arithmetic Operators

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

Arithmetic Operations

A typical arithmetic operation operates on two numbers.

The two numbers can be literals:

Example

let x = 100 + 50;

or variables:

Example

let x = a + b;

or expressions:

Example

let x = (100 + 50) * a;

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.

Adding

The addition operator (+) adds numbers:

Example

let x = 5;

let y = 2;

let z = x + y;

Subtracting

The subtraction operator (-) subtracts numbers.

Example

let x = 5;

let y = 2;

let z = x - y;

Multiplying

The multiplication operator (*) multiplies numbers.

Example

let x = 5;

let y = 2;

let z = x * y;

Dividing

The division operator (/) divides numbers.

Example

let x = 5;

let y = 2;

let z = x / y;

Remainder

The modulus operator (%) returns the division remainder.

Example

let x = 5;

let y = 2;

let z = x % y;

Note: 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.

Incrementing

The increment operator (++) increments numbers.

Example

let x = 5;
x++;

let z = x;

Decrementing

The decrement operator (--) decrements numbers.

Example

let x = 5;

 x--;

let z = x;

Exponentiation

The exponentiation operator (**) raises the first operand to the power of the second operand.

Example

let x = 5;

let z =
 x ** 2;

x ** y produces the same result as Math.pow(x,y):

Example

let x = 5;

let z =
  Math.pow(x,2);

Operator Precedence

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

Example

let x = 100 + 50 * 3;

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.

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

Example

let x = (100 + 50) * 3;

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

Examples

let x = 100 + 50 - 3;

Note: For a full list of operator precedence values go to: JavaScript Operator Precedence Values.