The CardChecksum function returns 1 for valid cards and 0 for invalid cards, after performing a check using the Luhn algorithm which validates all major credit cards.
Find The Greatest Common Divisor
Implement the Euclidean algorithm into a Python function in order to calculate the largest common divisor of two numbers.
Converting from binary to decimal and back
A simple method for converting binary numbers to decimal, and a wise method for converting decimal numbers to binary (using hexadecimal in between.)