Math 108 Topics in Mathematics | James Baglama |
16.1 Check Digits American Express Checks - Video

16.1 Check Digits American Express Checks - Video

Key Idea

The American Express Travelers Cheque uses a check digit determined by division by 9. The check
digit is the smallest nonnegative integer such that the sum of the digits, including the check digit,
is evenly divisble by 9.