International Standard Book Numbers are given to each new book which is published (xuất bản). If the sum of the 2nd, 4th, 6th, 8th, 10th, and 12th digits is tripled and then added to the remaining digits (1st, 3rd, 5th, 7th, 9th, 11th, and 13th), the total will always be divisible by 10.
For example, (7 + 3 + 6 + 4 + 4 + 0) × 3 + (9 + 8 + 1 + 1 + 8 + 1 + 0) = 100.
In the ISBN on the right, the 12th digit is hard to read: 978-0-90-65889?-7
What is the 12th...
Đọc tiếp
International Standard Book Numbers are given to each new book which is published (xuất bản). If the sum of the 2nd, 4th, 6th, 8th, 10th, and 12th digits is tripled and then added to the remaining digits (1st, 3rd, 5th, 7th, 9th, 11th, and 13th), the total will always be divisible by 10.
For example, (7 + 3 + 6 + 4 + 4 + 0) × 3 + (9 + 8 + 1 + 1 + 8 + 1 + 0) = 100.
In the ISBN on the right, the 12th digit is hard to read: 978-0-90-65889?-7
What is the 12th digit?
