Hexadecimal number system

In mathematics and computing, hexadecimal (also known as base 16, or hex) is a positional system that represents numbers using a base of 16. Unlike the common way of representing numbers with ten symbols, it uses sixteen distinct symbols, most often the symbols "0"–"9" to represent values zero to nine, and "A"–"F" (or alternatively "a"–"f") to represent values ten to fifteen.

In mathematics, a subscript is typically used to specify the base, also known as the radix. For example, the decimal value 10,995 would be expressed in hexadecimal as 2AF316. In programming, a number of notations are used to support hexadecimal representation, usually involving a prefix or suffix. The prefix  is used in C and related languages, which would denote this value by.

Usage
Hexadecimal numerals are widely used by computer system designers and programmers, as they provide a human-friendly representation of binary-coded values. Each hexadecimal digit represents four binary digits, also known as a nibble, which is half a byte. For example, a single byte can have values ranging from 00000000 to 11111111 in binary form, which can be conveniently represented as 00 to FF in hexadecimal.

Hexadecimal is used in the transfer encoding Base16, in which each byte of the plaintext is broken into two 4-bit values and represented by two hexadecimal digits.

Base theory
Due to being a power of 2 base, only fractions which are integral powers of 2 terminate (1/4 = 0x0.4). The omega 15 provides short reptends for thirds and fifths (1/5 = 0x0. 3), but they don’t terminate.