ISBN (short for International Standard Book Number) is an international standard number that is commercially unique to identify a book. The ISBN system, created in the UK in 1966 by book and stationery distributors W H Smith and friends, was originally called Standard Book Numbering or SBN. It was later internationally recognized by the ISO 2108 standard in 1970. A similar format, the International Standard Serial Number, or ISSN, is used for periodicals such as magazines. solstice.
Each copy and each change (unless reprint) of a book will have its own ISBN number. The number can have 10 characters (old style) or 13 characters (new style, applicable to barcodes), consisting of 4 or 5 parts.
If it is an ISBN with 13 digits, it has an EAN prefix of 978 or 979. See also EAN-13. If it is an ISBN number with 10 characters, then just assign the phrase "ISBN", or in countries where Latin characters are not used, vernacular abbreviations can be used instead,
Country code or language code,
number of the book,
Check digit. Different parts have different lengths and are usually connected by dashes. The strikethrough is not required, however, because the prefix is used to ensure that no two numbers begin with the same pattern. If present, dashes must be set correctly (rules are here Archived 2005-04-03 at the Wayback Machine. However, they are not sufficient as different authorities are responsible for allocating and implementing number intervals. ISBNs vary.There isn't even an up-to-date list on isbn.org's website.
Country codes (or language codes) 0 and 1 are used for English-speaking countries; 2 for French-speaking countries; 3 for German etc. (The original SBN number lacks the country code, but the 0 to 9 prefixes make up the complete ISBN.) Country codes can be up to 5 digits, for example 99936 for Bhutan. See the complete list of Archives 2009-07-22 at the Wayback Machine.
The publisher's number is assigned to that country's ISBN and the sequence number is chosen by the publisher of the book. It is not necessary for publisher products to have an ISBN number, but there is an exception for China. However, there are many bookstores that only distribute products with ISBN numbers.
An issuer receives a cluster of ISBNs for products, but when used up, additional ISBNs are received, so an issuer can have multiple ISBNs.
The International ISBN in its official guide  Archived 2009-01-14 at the Wayback Machine states that the 10th digit of the ISBN number sequence is the check digit, it is the last digit of a 10-digit ISBN sequence, calculated by division by 11 with weights 10 to 2, using X instead of 10 where 10 is the check digit. This means that each of the first 9 numbers of the 10-digit ISBN sequence – with the exception of the check digit – is multiplied by numbers in the order of 10 to 2 and the sum of these multiplications is added. for the check digit, must be divisible by 11.
For example, compute the check digit for a 10-digit ISBN sequence where the first 9 digits are 0-306-40615.