Hexadecimal numbers are often used in describing the data in computer memory. A computer memory stores a large number of words, each of which is a standard size collection of bits. An 8-bit word is known as a Byte. A hexadecimal digit may be considered as half of a byte. Two hexadecimal digits constitute one byte, the rightmost 4 bits corresponding to half a byte, and the leftmost 4 bits corresponding to the other half of the byte. Often a half-byte is called nibble.

If "word" size is n bits there are 2n possible bit patterns so only 2n possible distinct numbers can be represented. It implies that all possible numbers cannot be represent and some of these bit patterns (half?) to represent negative numbers. The negative numbers are generally represented with sign magnitude i.e. reserve one bit for the sign and the rest of bits are interpreted directly as the number. For example in a 4 bit system, 0000 to 0111 can be used to positive numbers from +0 to +2^n-1 and represent 1000 to 1111 can be used for negative numbers from -0 to -2^n-1. The two possible zero's redundant and also it can be seen that such representations are arithmetically costly.

Another way to represent negative numbers are by radix and radix-1 complement (also called r's and (r-1)'s). For example -k is represented as Rⁿ -k. In the case of base 10 and corresponding 10's complement with n=2, 0 to 99 are the possible numbers. In such a system, 0 to 49 is reserved for positive numbers and 50 to 99 are for positive numbers.