Why did the fortune teller know that I lived on the fifth floor after asking my birthday calculation? How to calculate?

For example, it is relatively easy to have your own attributes, such as time, orientation, up and down colors, etc. According to relatives, all the names in his family are calculated according to eight characters, including grandpa's real name. Obviously, this is not the realm that fortune telling can achieve. It's weird. It's not weird at all. After all, there are people outside the world.