For questions about "mathematics" in works of science fiction or fantasy. Also for use on [story-identification] questions.
Mathematics is the study and use of the abstract system that helps us explain how the physical world works.
At its simplest it is a basic numbering system used for counting and allocating, allowing us to easily keep track of quantities and values.
At its most complex it can represent laws of nature that govern everything from the structure of the universe (cosmology) to the construction of matter from sub-atomic elementary particles (particle physics).