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.
These larger and smaller units are called âderivedâ units. A) Length. The basic unit of length in the metric system is the meter (m). Common derived units are the centimeter (cm) (10-2 or 1/100 of a meter) and the millimeter (mm) (10-3 or 1/1000 of a meter).For measuring large distances, the kilometer (103 or 1000 meters) is often used.B) Volume.hese larger and smaller units are called âderivedâ units. A) Length. The basic unit of length in the metric system is the meter (m). Common derived units are the centimeter (cm) (10-2 or 1/100 of a meter) and the millimeter (mm) (10-3 or 1/1000 of a meter).