# Introduction to JavaScript – Math Operators

Introduction to JavaScript – Math Operators. Don’t worry! Math doesn’t need to be your strong-suit to learn JavaScript. However, there are operators you’ll need to know to make useful programs.

JavaScript supports the following math operators:

 Add: + Subtract: – Multiply: * Divide: /

These all work how you might guess: See sample code below.

```
console.log(3 + 4); // Equals 7
console.log(5 - 1); // Equals 4
console.log(4 * 2); // Equals 8
console.log(9 / 3); // Equals 3

```

In the example above, each line uses a different mathematical operator to log value to the console.

Go ahead and modify the code below and run it to view its output. Remember: the more you code the more you know.

## JavaScript Arithmetic Operators

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

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

## Arithmetic Operations

A typical arithmetic operation operates on two numbers.

The two numbers can be literals:

### Example

var x = 100 + 50;

Try it Yourself »

or variables:

### Example

var x = a + b;

Try it Yourself »

or expressions:

### Example

var x = (100 + 50) * a;

Try it Yourself »

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

var x = 5;
var y = 2;
var z = x + y;

Try it Yourself »

The subtraction operator (-) subtracts numbers.

### Subtracting

var x = 5;
var y = 2;
var z = x – y;

Try it Yourself »

The multiplication operator (*) multiplies numbers.

### Multiplying

var x = 5;
var y = 2;
var z = x * y;

Try it Yourself »

The division operator (/) divides numbers.

### Dividing

var x = 5;
var y = 2;
var z = x / y;

Try it Yourself »

The modular operator (%) returns the division remainder.

### Modulus

var x = 5;
var y = 2;
var z = x % y;

Try it Yourself »

The increment operator (++) increments numbers.

### Incrementing

var x = 5;
x++;
var z = x;

Try it Yourself »

The decrement operator (–) decrements numbers.

### Decrementing

var x = 5;
x–;
var z = x;

Try it Yourself »

## Operator Precedence

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

### Example

var x = 100 + 50 * 3;

Try it Yourself »

Is the result of the 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;

Try it Yourself »

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;

Try it Yourself »

## JavaScript Operator Precedence Values

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)
15 typeof Type typeof x
15 ** Exponentiation 10 ** 2
14 * Multiplication 10 * 5
14 / Division 10 / 5
14 % Modulo division 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
10 == Equal x == y
10 === Strict equal x === y
10 != Unequal x != y
10 !== Strict unequal x !== y
6 && Logical and x && y
5 || Logical or 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
3 |= Assignment x |= y

Pale red entries indicates experimental or proposed technology (ECMAScript 2016 or ES7)

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

See the JavaScript Glossary on Basic Arithmetic

See the JavaScript Glossary on the Math Library

JavaScript Glossary

Introduction to JavaScript – Variables: Mathematical Assignment Operators

## About the Author: Bernard Aybout

In the land of bytes and bits, a father of three sits, With a heart for tech and coding kits, in IT he never quits. At Magna's door, he took his stance, in Canada's wide expanse, At Karmax Heavy Stamping - Cosma's dance, he gave his career a chance. With a passion deep for teaching code, to the young minds he showed, The path where digital seeds are sowed, in critical thinking mode. But alas, not all was bright and fair, at Magna's lair, oh despair, Harassment, intimidation, a chilling air, made the workplace hard to bear. Management's maze and morale's dip, made our hero's spirit flip, In a demoralizing grip, his well-being began to slip. So he bid adieu to Magna's scene, from the division not so serene, Yet in tech, his interest keen, continues to inspire and convene.