[axonic]

For Algebra, if you need certain subjects in depth or need to take a test to assess your skills, try Khan Academy [1]. Also, Khan covers trigonometry and geometry. For Calculus, MIT did a series called Calculus Revisited which covers calc 1,2,3.[2] Calculus Revisited was designed for professionals who needed a refresher or first crash course. It's from 1968-72 but I thought they were great.

[1] https://khanacademy.org [2] https://ocw.mit.edu/resources/#Mathematics