LETTERS TO THE EDITORS
Zipping Along
To the Editors:
One topic not touched upon by Brian Hayes's article, "Naming
Names" (January-February) was the zip code system. In the U.S.,
a zip code has just five digits, so the maximum number of codes for
some 300 million people is 99,999, or roughly one code for every
3000 people. (Editor's note: Only about 42,000 of the
possible codes are in use.) The use of the four additional figures
in the zip + 4 system vastly increases the permutations and yields
three codes per US resident but makes a rather unwieldy nine-digit
code. In Canada, we use a six-way combination of letters and
numbers. My post code is T4R 1T2. The maximum number of combinations
is therefore 17,576,000, or just over one code for every two
Canadians. Thus a portion of a street or even each office building
has its own distinct postal code. Since the North Pole is apparently
in Canada, Canada Post has given Santa Claus the code H0H 0H0.
Grant L. Nielsen
Red Deer, Alberta