Can you explain how credit card numbers work in detail?

Credit card numbers are typically 16 digits long and follow a specific pattern. The first digit identifies the type of card, the next digits represent the bank that issued the card, and the remaining digits are unique to each card. A mathematical formula called the Luhn algorithm is used to validate the number and ensure it is legitimate. When a credit card is used for a transaction, the number is verified by the issuing bank to authorize the purchase.