A position on defense commonly in the defensive backfield. The strong safety plays in the middle of the field on the strong side of the formation, closer to the line of scrimmage than the free safety. The strong safety is more involved in stopping the run and guarding the tight end on passing plays. The strong safety tends to be the larger of the two safeties, and he must be a sure tackler with solid cover skills.
From Wikipedia, the free encyclopedia. A check digit is a form of redundancy check used for error detection on identification numbers, such as bank account numbers, which are used in an application where they will at least sometimes be input manually. It is analogous to a binary parity bit used to check for errors in computer-generated data.
The check digit of an ISBN is calculated in a more complex way than the check digit of a PostNET code. For an ISBN check digit, multiply the first digit by 10, the second digit by 9, the third digit by 8, ..., the ninth digit by 2 and add up all these numbers. The check digit is the number you have to add to this total to get up to a multiple of 11. So, for the second example given above, we would calculate: