Here are some additional useful rules when working with the comma.
Use a comma after the salutation of a friendly letter.
Use a comma after the closing in a friendly or business letter.
Use a comma to separate items in dates and addresses.
She was born on January 4, 1993, in Baton Rouge, Louisiana.
The family’s current address is 1600 Pennsylvania Avenue,
Note: A comma is not needed
• between the month and the day—April 18, 2010
• between the month and the year (when no day is offered)—
• between the state (or state’s abbreviation) and the ZIP Code—
Canton, MA 02021
• between the house or apartment number and the street—
204 Joyner Court or Apartment 6A Twelfth Street
Use a comma to separate the speaker from the speaker’s
Trey remarked, ‘‘This blanket was already washed.’’
‘‘My car needs new tires,’’ Gabriella said.
Note: Place the period and comma within the closing quotation marks.
Use a comma after a mild interjection.
Oh, I didn’t realize that you were here, Nana.
Note: Use an exclamation mark after a strong interjection.
Rats! I left my wallet at the beach.