Matrices, vectors, vector spaces, transformations. Covers all topics in a first year college linear algebra course. This is an advanced course normally taken by science or engineering majors after taking at least two semesters of calculus (although calculus really isn't a prereq) so don't confuse this with regular high school algebra.

Videos on pre-algebra. Should be ready for the "Algebra" category if you understand everything here.

Topics covered in the first two or three semesters of college calculus. Everything from limits to derivatives to integrals to vector calculus. Should understand the topics in the pre-calculus category first

Non-trigonometry pre-calculus topics. Solid understanding of all of the topics in the "Algebra" category should make this category pretty digestible.

The most basic of the math categories. Start here if you have very little background in math fundamentals (or just want to make sure you do). After watching this category, you should be ready for the pre-algebra category.

Topics covered in a first year course in differential equations. Need to understand basic differentiation and integration from Calculus category before starting here.

Topics covered from very basic algebra all the way through algebra II. This is the best algebra playlist to start at if you've never seen algebra before.

Videos on trigonometry. Watch the "Geometry" category first if you have trouble understanding the topics covered here.