In the feeling of power by end story what has Jehan shuman learned too do?

It seems you're referring to the short story "The Feeling of Power" by Isaac Asimov. In this story, Jehan Shuman, a historian, discovers a way to perform calculations far beyond the capabilities of the powerful computers of his time. He does this by exploiting the basic principles of binary code that are the foundation of modern computers.

Specifically, Jehan learns:

* To think in binary: He figures out how to break down complex problems into a series of simple "yes" or "no" questions, which can be represented by the 1s and 0s of binary code.

* To perform calculations mentally: By mimicking the logic gates of a computer in his mind, he can perform complex calculations at incredible speed.

* To control information: He realizes that by understanding and manipulating binary code, he can control vast amounts of information, potentially even manipulating the flow of information in his society.

The story explores the power of knowledge and the potential dangers of its misuse. While Jehan starts off with a desire to share his discovery, he ultimately chooses to keep it secret, fearing the consequences of a world where individuals are empowered by direct access to information.