Hexadecimal notation is a numbering system that uses a base (radix) of 16. Unlike decimal notation (base 10) or binary notation (base 2), uses 16 digits: 0,1,2,3, 4, 5, 6, 7,8, 9, A, B, C, D, E, and F. Programmers use as a convenient way to represent binary notation, which is difficult to read and prone to error when manipulated by humans. The two notational systems are easily translated into one another because 16 is a power of 2. In contrast, decimal numbers are more difficult to translate into binary numbers because they are in base 10, and they are not a power of 2. So also each hexadecimal number can represent 16 quantities, a single hexadecimal number can stand for four binary digits (for example, 1111 [15 in decimal] = F [hexadecimal]). See binary notation, byte, decimal notation, octal notation.
Technipages Explains Hexadecimal Notation
Hexadecimal is a numbering system used by programmers to simplify the binary numbering system. Using and understanding the binary numbering system can sometimes be hard for programmers to use, as computers use binaries, but programmers use the hexadecimal numbering system to simplify the binary codes. The notation is in base 16, and it is made up of 16 digits: 0 – 9 and six more, which is A through to F.
In the binary system, 16 is equivalent to 24, and there is a linear relationship between the numbers 2 and 16, hence, the relationship between the binary notation and the hexadecimal notation. It means that one hexadecimal digit is equivalent to four binary digits. It can be used to write large binary codes in just simple digits, and this makes it more humanfriendly.
Hexadecimal is a helpful method to express binary numbers in presentday PCs in which a byte is quite often characterized as containing eight binary digits. When demonstrating the substance of PC stockpiling, one hexadecimal digit can speak to the course of action of four binary digits. Two hexadecimal digits can speak to eight binary digits or a byte.
Common Uses of Hexadecimal Notation

You can use StandardColors or common color codes: hexadecimal notation

To include arbitrary characters into a string using octal or hexadecimal notation.
 The decimal number “10” in hexadecimal notation, is “A”.
Common Misuses of Hexadecimal Notation
 Hexadecimal Notations were used to write poetic letters in the early days of human evolution