To find out whether your card is the primary or secondary card number, you must first know how to check a credit card.

If you want to check the card number of a credit card supplementary card, the method is actually the same as checking the card number of the main credit card. In fact, the detailed card number is usually marked on the face of each credit card, so customers can know the specific card number (usually 16 digits) by taking out the card.

If the customer does not have the card with him and needs to know the card number at the moment, he can also log in to the issuing bank’s personal online banking, mobile banking client or credit card APP, and click the card on the personal account interface. Select the card you want to query from the list, and click to enter the details page to find the specific card number. Some may hide part of the card number. For this, customers can usually expand all card numbers by entering the information management page.

Of course, customers can also directly call the customer service number of the card-issuing bank, transfer to manual service, and ask the bank's customer service staff. After verifying that the customer's identity information is correct, the customer service staff will inform the customer of the specific card number. Alternatively, customers can go to the counter of a nearby branch to inquire with staff with their valid personal identity documents.