When you include a full date (month, day, and year), use a pair of commas to set off the year.

If you present a date in reverse order (day, month, and year) or if the date is partial, do not add commas.

In large numbers (except four-digit years), separate groups of three digits (thousands, millions, and so forth) with commas.

When you write out an address, add commas between the street address, the city, and the state.