Dear Ed Rauh

How are you? Do you know about ISBN (International Standard Book Number)?
If you know about, please tell me how i can validate isbn. I remembered that there was a FORMULA to calculate the valid ISBN whose resulting value is ZERO.
I want you to give that formula, or any other calculation method which can fulfill my requirement.

I have project from Bookseller's company. Company want to control there inventory with books having ISBN. When they enter new title's isbn, some routine should validate whether it is this valid number or not.

I will be highly obliged if you kindly let me know as soon as possible.

Thank you,