Why can fortune tellers work out other people's names and surnames?

Of course, this is a lie. We have studied permutation and combination in mathematics, and there are certain rules to be found. For example, if you take out a piece of cardboard with your surname Wang written on it, of course, there are many surnames on it, and then cover it with a piece of cardboard with your surname Wang written on it (there are also many surnames on the cardboard below), of course you will know your surname Wang, because there is only one surname Wang repeated on two pieces of cardboard, as simple as that. Similarly, other surnames are the same, so it can be concluded that you can measure your surname, your home address, your age, the zodiac, the zodiac and so on. Of course, before the test, we must sort out and combine the measured items.