Hexadecimal is the base system using base sixteen. Typically, the sixteen symbols for hexadecimal are represented as 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F in order; sometimes, the letters A, B, C, D, E, and/or F are all lowercase instead of all uppercase. As with other base systems, numbers can be efficiently added, subtracted, multiplied, and divided in hexadecimal.

## Applications

Hexadecimal is most commonly used in computer science, as it is a human-friendly way to represent numbers (or more general forms of data) that have been stored in binary.

### Color Codes

Color codes are commonly expressed in hexadecimal. A hexadecimal color code is six digits, the first two representing the red value, the next two representing the green value and the last two representing the blue value. It is used so that all the numbers from 0 to 255 can be expressed in two digits. For example, the color code #FF0099 represents (255,0,153) in RGB (since $9\cdot16+9=153$) and is a nice pink color. It is comprised of 255 parts red to 0 parts green to 153 parts blue.