Hexadecimal is 16 based and uses the digits 0 to 9 and the letters

**a**to

**f**to represent the values 0 to 15. Letters are used after values past nine as two digits can not be used. Hexadecimal is used more often than octal as any four bits of a binary number can be converted into its hexadecimal equivalent and vice-versa. The number 345 in hexadecimal is 837 as a decimal.

An eight bit binary number can be converted into its hexadecimal equivalent easily. For example, convert 11111111 into hexadecimal. (The answer is ff).

- Break the number into two lots of four bits: 1111 1111
- Convert each lot into its decimal equivalent: 1111 => 15, 1111 => 15
- Convert these into hex: 15 => f, 15 => f.
- Concatenate them: f and f => ff.