One of the most important mathematical books ever written, Principia Mathematica, needed 360 pages to prove that 1 + 1 = 2. The book itself is considered so advanced and hard to understand that it’s rarely used in academia at all.
A deceased man was considered a coauthor of a 1990 math paper after he appeared in a dream to the other author to explain some of the key ideas.
A Futurama episode contains a real-life mathematical theorem which was specifically made for that episode, making it the first known theorem to be created for the sole purpose of entertainment in a TV show.
When the mathematician George Dantzig was studying in Berkeley, he solved two open problems in statistical theory which he had mistaken for homework after arriving late to a lecture.
There are 7 math problems whose solutions are worth 1 million dollars. Only one has been solved.