For example, the ubiquitous UPC code uses weights of 1 and 3 for alternate numbers with digit 1 being the rightmost digit (other than the check digit) followed by digits 2, 3, and so on moving to ...

There are examples of this all around us and we sometimes don’t even know it. For example, what do your credit card number, your car’s VIN code, and a UPC code on a can of beans have in common?