Companies that issue credit cards also use modular arithmetic to determine whether a credit card number is valid. This is especially necessary in e- commerce, where credit card information is frequently sent over the Internet. The primary ... Arithmetic 419. Card Issuer Prefix Number of digits MasterCard 51 to 55 16 Visa 4 13 or 16 American Express 34 or 37 15 Discover 6011 16 X A W Q P u Y B X R.
|Author||:||Richard N. Aufmann|