• Math

    Barcodes and Modular Arithmetic

    Barcodes Here is an example of a UPC-A barcode, taken from wikipedia: A UPC-A barcode has 12 digits.  The first digit is something that tells how the numbers are generally used – for example, a particular industry might use a certain number for certain kinds of items.  The last twelfth digit is a check digit that can try to tell whether or not the numbers have an error.  This check digit is constructed in a certain way at first.  Later on, the check digit may be able to tell us if the numbers have an error or not.   The check digit is constructed as follows: We have 11 digits:…