Hexadecimal (English name: hexadecimal) is the representation of data in a computer.

It is different from our daily life. It consists of 0-9 and A-F, and letters are case-insensitive.

The corresponding relationship with 10 is: 0-9 corresponds to 0-9; A-F corresponds to10-15; N-ary numbers can be represented by numbers from 0 to (n- 1), and those exceeding 9 are represented by letters A-F. ..

The cardinal number of 16 is from 16 to 1, but we only have ten numbers from 0 to 9, so we use the letters a, b, c, d, e and f to represent 10,1and/respectively.