Mathematics The language every other exact science speaks. Almost every chain starts here 27 courses, 693 lecture recordings, about 494 hours. Courses in the order you learn them Analytic geometry School mathematics Calculus 1 Discrete mathematics Linear algebra Abstract algebra Calculus 2 Combinatorics Graph theory Number theory Algebraic geometry Calculus 3 Lie groups and Lie algebras Numerical methods Real analysis Complex analysis Differential equations Game theory Measure theory Optimization methods Topology Category theory Differential geometry Dynamical systems Functional analysis Partial differential equations Mathematical physics The map of knowledge