in ZIP Code stands for Zone Improvement
The bar-code system used by the US Postal
Service is called Postnet.
The bar code found on most supermarket
items is a UPC type A. Such codes consist of
12 digits. When space
does not allow 12 digits, a
UPC type E codewhich is only
8 digitsis used.
The US grocery
industry formally adopted the UPC system in
The mission of
the Uniform Code Council, based in Dayton, Ohio,
is to take a global leadership role in establishing and
promoting multi-industry standards for product identification
and related electronic communication.
Bar codes are also used by libraries,
airlines, and blood banks.
After the ZIP
Code bars, the next two groups of five bars represent
the delivery code for the mail on the primary street address.
The last set of bars in the code represents
a check digit that helps a computer determine if the first
digits have been read correctly. The check
digit at the end of a US Postal Service code is calculated
by adding the 11 previous digits
in the the code, then identifying
the smallest digit that can be added to this sum to obtain
a multiple of 10. For example, the check digit
for the postal code in the Challenge is 3, since:
5 + 9 + 8 + 0 + 1 + 2 + 7 +
1 + 7 + 3 + 4 = 47
and the smallest positive number that can
be added to 47 to produce a multiple of 10 is 3.