If you want to get better at geometry a very good start is brilliant.org. They have five great geometry course that's good for learning concepts visually and ha

If you want to get better at geometry a very good start is brilliant.org. They have five great geometry course that's good for learning concepts visually and has some basic exercises, but not enough for drilling. When it comes to exercises, brilliant.org is lacking in volume. Khan Academy is a great supplement for geometry, single and multivariable calculus although brilliant.org goes a bit further than Khan Academy with Linear Algebra, Group Theory and more. Khan Academy also has a linear algebra course, but I found it to be kinda crap with no exercises. For linear algebra it's better go with brilliant and 3blue1brown's linear algebra videos, then a good continuation would be Linear algebra done right by Sheldon Axler and also fast.ai's free online course Computational Linear Algebra for Coders.