 An example of an apartment number would be 412—on the first floor (1) of building 4 or building 400, or 1204—on the ground floor (0) of building 12 or building 1200.Apartments are usually numbered using the floor number postfixed with the "side" designation, where the floor numbers go st. (ground floor), 1., 2., 3. etc and the post-fix "tv" (to the left), "mf" (in the middle) or "th" (to the right).Example address