Mathematical coding:

1, get a preliminary understanding of the structure and meaning of postal codes and the meaning of local postal codes.

2. Understand the meaning of ID code.

Digital coding:

1, which is convenient for filing, especially in the electronic management system.

2. Digital coding is easier to manage. No matter who codes it, it's the same. Easy to manage. No matter how people change, procedures and transactions will not be chaotic.

3. Detailed corresponding information can be obtained from the numbers, such as year, month, day, even hour, minute, second, unit, department, archivist and so on.

4, familiar with digital coding can quickly locate files.