Board Thread:News and Announcements/@comment-5047768-20131003005753/@comment-3406131-20131003233215

Only on a few occasions. Most of the time you have to look for in such sites as the appendix/marvunapp (http://www.marvunapp.com/master/earthteaz.htm#numbered), or on some handbooks.

There is some universes that are common to some series: etc. But the times the comics specify itself the earthes explored, using their numbers instead of their names are really few.
 * Earth-616 is the mainstream universe, the one where happens pretty much everything, and the major line from which diverges into alternate/future earths.
 * Earth-1610 is the ultimate universe, for every Ultimate-title series
 * Earth-199999 for the Avengers/Iron Man/etc movies, SHIELD series (+comics and games related to the movies)
 * Earth-10005 for the X-Men Movies (+comics and some games, related to the movies)
 * Earth-TRN123 for the current anime lines (Ultimate Spider-Man, Avengers Assemble, Hulk Agent of SMASH), TRN (temporary reality number) designing earths with no official designation.
 * Earth-928: The first waves of series occurring in Marvel 2099