The comma is the most frequently used internal mark of punctuation. Of all the marks of punctuation, it has the widest variety of uses.
Using commas with dates, addresses, greetings, names, and large numbers
* Commas are used with full dates (month, day, and year) but omitted with partial dates (month and year):
1. Gas has been first used by the Germans on October 14, 1914, when they fired a prototype of modern tear gas from artillery near Pyres. Paul Fussel
2. In June 1985 Beth Henley was working on her fifth play.
Exception: No comma is used to separate parts of a date that begins with the day.
The atomic bomb was first dropped on 6 August 1945.
* Commas are required between most of the elements in place names and addresses:
1. Miami, Dade County, Florida
2. Writing Lab, University of California, Riverside
Exception: # Do not use comma to separate street number from the name of the street:
15 Amsterdam Avenue
# Do not use comma to separate a state from zip code:
5625 Waverly Avenue, La Jolla, California 92037
* In complete sentence, a comma must follow the last element of place...