Hexadecimal

In mathematics and computing, hexadecimal (also base 16, or hex) is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F (or alternatively a–f) to represent values ten to fifteen. Hexadecimal numerals are widely used by computer systems designers and programmers. In computing, hexadecimal numerals are usually written with a prefix, "0x" (in reference to the abbreviated pronunciation of "hexadecimal"). Alternately, some authors denote hexadecimal values using a suffix or subscript. For example, one could write 0x2AF3 or 2AF3₁₆, depending on the choice of notation.
As an example, the hexadecimal number 2AF3₁₆ can be converted to an equivalent decimal representation. Observe that 2AF3₁₆ is equal to a sum of (2000₁₆ + A00₁₆ + F0₁₆ + 3₁₆), by decomposing the numeral into a series of place value terms. Converting each term to decimal, one can further write: (2₁₆ × 16³) + (A₁₆ × 16²) + (F₁₆ × 16¹) + (3₁₆ × 16⁰), (2 × 4096) + (10 × 256) + (15 × 16) + (3 × 1), or 10995.
Each hexadecimal digit represents four binary digits (bits), and the primary use of hexadecimal notation is a human-friendly representation of binary-coded values in computing and digital electronics. One hexadecimal digit represents a nibble, which is half of an octet or byte (8 bits). For example, byte values can range from 0 to 255 (decimal), but may be more conveniently represented as two hexadecimal digits in the range 00 to FF. Hexadecimal is also commonly used to represent computer memory addresses.