Our institute has contributed a station to the JKU program of the Long Night of Research 2022. We explained there to the general public that arithmetic is not strictly tight to numbers but that addition and multiplication also make sense for other objects. Visitors had the possibility to simplify expressions and to solve equations in computational universes which only contain four or five "numbers", instead of the common number spaces that all contain infinitely many numbers. Such finite number spaces are not only fun but they are important tools for significantly reducing the computation time in large scientific computations. They also have applications in cryptography and in coding theory.