HS Math Subject is a term used to refer to the two math courses typically offered in high school: Algebra and Trigonometry. Algebra is a branch of mathematics that uses symbols and equations to represent and solve problems. Trigonometry is a branch of mathematics that studies the relationships between angles and sides of triangles. Both Algebra and Trigonometry are important components of a high school math curriculum, and are essential for students who plan to pursue higher education in mathematics or related fields.