Success said:
List as many math subjects as possible. But they need to be in order.
With regards to undergraduate math courses (and beyond) there is no set, linear order. Instead, there are "branches" where different courses fall. The three main branches are:
1) Analysis: Real analysis, complex analysis, ordinary diff. eq., partial diff. eq., harmonic analysis, functional analysis, ...
2) Algebra: abstract algebra, number theory, linear algebra, commutative rings/algebras, associative rings/algebras, ...
3) Geometry/topology: geometry, topology, differential geometry, algebraic topology, manifolds, ...
One could argue that logic & set theory is a fourth branch. Applied mathematics (numerical analysis, probability/statistics, operations research, game theory, ...) could be a fifth branch.