Magicians do a “mentalist” trick where they ask someone to think of a random number and then they guess it. There are various ways to pull this off and none involve hypnosis or telepathy. Usually, the mentalist is setting some hidden constraints to ensure that the chosen number isn't really random. They also rely on their ability to read body language and get help from secret assistants.
Creating a truly random number, or a set of random numbers, is surprisingly difficult. It is also really important. Random numbers, which are unpredictable and hard to guess, are crucial for cryptography and secure