Tetraphobia
Chinese people take care not to use the number 4 during important holidays, or if someone in the family is sick. Numbers such as 14, 24, and so on, are not used because they also have the number 4 in them. Buildings sometimes do not have floors with these numbers, apartments and hotels do not have rooms with number 4, 14, 24 and so on. Table number 4, 14, 24, may be often left out in wedding dinners or other social activities in these countries. Where there are a lot of apartment buildings, buildings that should be 4, 14, 24, are called 3A, 13A, 23A, and so on.