The hip is a ball-and-socket joint. The socket is formed by the acetabulum, which is part of the large pelvis bone.The ball is the femoral head, which is the upper end of the femur (thighbone).he hip is a ball-and-socket joint. The socket is formed by the acetabulum, which is part of the large pelvis bone.
Most of us carry credit cards and ATM cards. These, typically, have sixteen digits on the front. These digits are the unique account number for the card. For obvious reasons, just any sixteen digits will not work, they follow pattern. The first few characters of the card number describe the type of card.
Credit card numbers follow certain patterns. A credit card must have between 13 and 16 digits. It must start with: â¢ 4 for Visa cards. â¢ 5 for Master cards. â¢ 37 for American Express cards. In 1954, Hans Luhn of IBM proposed an algorithm for validating credit card numbers. The algorithm is useful to determine if a card number is entered correctly or if a credit card is scanned correctly by a scanner.