Definition:International Standard Book Number
Definition
An international standard book number is an index number used to uniquely identify a published book.
ISBN-$10$
The ISBN-$10$ format consists of a string of $9$ digits followed by a check digit in the set $\set {0, 1, \ldots, 9, X}$.
The check digit $d$ is calculated as follows.
Let $c$ be calculated as:
- $c = \ds \sum_{k \mathop = 1}^9 k d_k \pmod {11}$
where $d_k$ denotes the $k$th digit in the ISBN-$10$.
Then the check digit $d$ is defined as:
- $d = \begin {cases} c & : c \le 9 \\ X &: c = 10 \end {cases}$
ISBN-$13$
The ISBN-$13$ format consists of a string of $12$ digits followed by a check digit.
The check digit $d$ is calculated as:
- $d = \ds \sum_{k \mathop = 1}^{12} k d_k \pmod {10}$
Also known as
An international standard book number is usually referred to by its abbreviation ISBN.
Linguistic Note
When referring to an international standard book number by its abbreviation ISBN, beware not to vocalise it as "ISBN number".
The word number is already included in the abbreviation ISBN, so does not need to be repeated.
Sources
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): ISBN