Algebra

This is used often to describe the "math" taught in High School Algebra and College Algebra courses. That arguably could fall into algebra, but I would rather place it in the general rudimentary prerequisites needed for a serious study of mathematics.

Algebra, as the term is generally used by anyone knowledgeable about math, is the study of algebraic objects. These are objects endowed with certain Binary Operations. Thus algebra includes the study of Groups, Rings, Modules, and Fields. Algebra originated as the study of equations, and it can still be seen as such.