The check digit is used to confirm the initial digits of the card number. The benefits of using a checksum is that it prevents casual attempts to invent credit card numbers, as only one in ten will be valid.
Length (adj). the longest, or longer, dimension of any object, in distinction from breadth or width; extent of anything from end to end; the longest line which can be drawn through a body, parallel to its sides; as, the length of a church, or of a ship; the length of a rope or line.
The lionâs mane jellyfish, Cyanea capillata, is sometimes stated as the worldâs longest animal with the largest specimen recorded at 37m from bell to tentacle tip. The bell, the body of the jellyfish, can be 2m in diameter.