# Hexadecimal

The hexadecimal number system is the base 16 number system (as distinct from our familiar base 10 decimal number system.) It traditionally uses the digits $\mathrm{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F},$ where $\mathrm{A}$ through to $\mathrm{F}$ represent the (decimal) numbers $10$ through to $15$. Sometimes the lower case $\mathrm{a}$ through to $\mathrm{f}$ are used instead.

It is commonly used in computing, as $16=2^4$ represents $4$ binary digits (also known as bits), so a two digit hexadecimal number represents $8$ binary digits, which is known as a byte. Computer storage is described in bytes; for example, a 1 TB disk stores 1 terabyte, which is about $10^{12}$ bytes.