ISBN (International Standard Book Number)

I know many of us say that we didn’t learn anything of value in high school, but I think I have just forgotten it all. When I was a junior in Albert Sidney Johnston High School in Austin, Texas I had a wonderful Algebra II teacher, Mr. Schwartzman. He must of written a book because he was very focused on the ISBN. He showed us a mathematical formula for determining if the book had the correct ISBN number. It utilized the number after the hyphen, but other than that, I can’t remember. It has only been a short 25 (twenty-five) years, but my memory is fading fast. Can you help?

To minimize threads, thanks in advance!!!

Wikipedia has more than you could ever want to know about ISBN check digits.

Lots of other big numbers use check digits as well, like credit cards and UPC codes.

English teacher wasn’t quite as wonderful?

Must not of been.

Perhaps this is the book.

According to ABEBooks, from January 1st new ISBNs are going to be 13 digits instead of the present 10. Luckily the search facility on their website will work with both formats.

Depending on perspective, I have a hard time cataloging my books with most major options (such as because I have many that predate the ISBN numbers, most certainly predate UPC codes and putting the wrong info into a database, is, well, wrong.

I have the page opened to learn all I want to know about ISBN, so maybe I can figure out what number the books WOULD have had, had they been published in that era.

Then again, I do wish to catalogue my books according to the dewey decimal system and have a card file just like libraries USED to. How I miss those.