A numeric digit used to ensure that account numbers are entered accurately into the computer. Check digits are computed when the numbers are generated, and they become part of the number, often at the ...

calcCheckDigit calculates a check digit for a given record number. The given record number can be a string or a number. Regardless, the returned check digit will be a string. addCheckDigit calculates ...

I prefer to use the long form, with the record type prefix and check digit. It avoids ambiguity, and it's simpler for library staff to deal with. It's easy to go from the long form to the short form, ...

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory. She reports on topics from maths and history to society and animals. Katie has a PhD in maths, ...

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 ...

Computers in working order and with correct software don’t make mistakes. People, however, make plenty of mistakes (including writing bad software or breaking computers). In quality circles, there’s a ...