# JavaScript Data Type: Numbers

Numbers in JavaScript are stored in 64-bit format IEEE-754, also known as **double precision floating point numbers**.

In JavaScript, you shorten a number by appending the letter "e" to the number and specifying the zeroes count. In other words, "e" multiplies the number by 1 with the given zeroes count. For example:

var billion = 1e9; // 1 billion, literally: 1 and 9 zeroes

alert(5.4e6); // 5400000

A negative number after "e" means a division by 1 with the given number of zeroes. For example:

alert(2e-4); // 0.0002

### Hex, Binary and Octal Numbers

**Hexadecimal numbers** are widely used in JavaScript to represent colors, encode characters, and for other things. There exists a shorter way to write them: 0x and then the number. For example:

alert(0xff); // 255

**Binary and octal numeral systems** are rarely used, but also supported using the 0b and 0o prefixes. for example,

var a = 0b11111111; // binary form of 255

var b = 0o377; // octal form of 255

alert(a == b); // true, the same number 255 at both sides

### Rounding Numbers

One of the most used operations when working with numbers is rounding. There are several built-in functions for rounding:

**Math.floor**

Rounds down: 3.1 becomes 3, and -1.1 becomes -2.

**Math.ceil**

Rounds up: 3.1 becomes 4, and -1.1 becomes -1.

**Math.round**

Rounds to the nearest integer: 3.1 becomes 3, 3.6 becomes 4 and -1.1 becomes -1.

**Math.trunc**

Removes anything after the decimal point without rounding: 3.1 becomes 3, -1.1 becomes -1.

### Math Functions

JavaScript has a built-in Math object which contains a small library of mathematical functions and constants.

**Math.random()**

Returns a random number from 0 to 1 (not including 1).

alert('Random Number: ' + Math.random());

**Math.max(a, b, c) / Math.min(a, b, c)**

Returns the greatest or smallest from the arbitrary number of arguments.

**Math.pow(n, power)**

Returns n raised the given power