the card number of an associated bank should be two bank cards of the same bank, namely, a first-class card and a second-class card, where one card is the associated account number of the other, and this question refers to the last six digits of the account number of the first-class card.

First, the significance of bank card association.

(1) Bank card association means that after a user applies for a certificate, he associates his bank card with this certificate, so that all bank cards can be operated through one certificate.

(2) Because "bank card association" is very important, users are required to go to the bank counter to handle it. If the bank card is not associated with the user certificate, even if the customer has the certificate, the business function of the bank card cannot be used.

(3) Credit Card Bank Card Association Automatic Repayment Bank Card Association means that all your bank cards can be associated and transferred to each other, such as China Merchants Bank's one-card and credit card. If they are associated, you can use the money in the one-card to directly return it to the credit card on the online banking, or if you have one-card that is a salary card and one that you do yourself, you can also transfer money online and at an ATM. If you don't make association, you can't do the above things. If Alipay is associated with a bank card, it can only be withdrawn.

(4) If you only do online shopping through Alipay, you don't need to associate a bank card.

(5) It's no good to associate two debit cards. If one debit card is associated with one credit card, you can automatically repay the credit card for free, so as not to miss the repayment period. Second, the classification of bank cards is:

1. According to the storage medium, bank cards can be divided into magnetic stripe cards, chip cards and composite cards with magnetic stripes and chips.

2. Classification by function: Bank cards can be divided into credit cards and debit cards.

3. by settlement currency: bank cards can be divided into foreign currency cards and local currency cards.

4. by the number of account currencies: bank cards can be divided into single-currency cards, dual-currency cards and multi-currency cards.

5. according to the subordinate relationship, bank cards can be divided into main cards and subsidiary cards.