Are ISBN numbers ever different?

[Lori]

This book (hardcover) has the last digit of the ISBN 13 and 9 as different numbers (4 vs.9). The copy of the book I have only has the 13 number on the copyright page. I _thought_ that the two ISBNs are always the same except for the 9780 at the beginning.

Please help!
Lori Reeser

[Arenda]

Lori wrote: "This book (hardcover) has the last digit of the ISBN 13 and 9 as different numbers (4 vs.9). The copy of the book I have only has the 13 number on the copyright page. I _thought_ that the two ISB..."

The last number from both 10 and 13 ISBN is a control digit. The numbers after 978 are the same, with exception of the last number. It is calculated with the other numbers from the ISBN.
See also this link: http://en.wikipedia.org/wiki/Internat....

[Cloudedleopard]

ISBN 10 and 13 are often different (especially the last digit as it only represents a so-called "check digit"). ISBN 13 usually begins with 978 or 979, the next digit is the country code (here 0 for english speaking countries), afterwards you have some characterizing digits for the publisher and so on.

[Lori]

EEK!
I've been adding ISBN numbers using the same number after the 9780. I'll go back and check what I've done.

Thanks for letting me know.

[Krystal109]

Use an ISBN converter if you KNOW a book has an ISBN10 that is not listed. Not all books have an ISBN 10 and 13, so it is better to leave it blank than incorrectly adding one.

[rivka, Former Moderator]

Correct. Especially if published in the past 2-4 years, books may only have an ISBN13, and not an ISBN10.

[Lori]

I didn't know that. I thought all(new) books had both numbers.
Thanks for the info. I'm slowly changing my owned books to the correct edition, and I'm checking/updating info as I go along. This will help.