The last digit X of the ID number stands for 10. The last digit of the ID card may be 0 ~ 10 * * * 1 1 digit. So according to the probability, the last one is X, accounting for one eleventh of the country, which is about 9%.
The last x is capitalized. As the tail number, the check code is calculated by the numbering unit according to the unified formula. If a person's suffix is 0-9, X will not appear, but if the suffix is 10, then X must be used instead.
Extended data:
Structure and form of ID number
1, number structure
Citizenship number is a characteristic combination code, which consists of 17 bit ontology code and check code. The order from left to right is: six-digit address code, eight-digit date of birth code, three-digit serial code and one-digit check code.
2. Address code
The administrative division code of the county (county-level city, flag, district) where the permanent residence of the coding object is located shall be implemented according to GB/T2260.
3. Date of birth code
Indicates the year, month and day when the coded object was born, which is implemented according to GB/T7408. There is no separator between the year, month and day codes.
4, serial code
It refers to the serial number of people born in the same year, month and day in the area identified by the same address code. Odd numbers of serial numbers are assigned to men and even numbers to women.
5. Check code
According to the previous 17 bit code, the check code is calculated according to the check code of ISO 7064: 1983. MOD 1 1-2。
Baidu Encyclopedia-Resident ID Number