Since you don't have a goal, it's hard to recommend anything specific. Some good pointers - Khan Academy is great because it covers a lot of material at school

Since you don't have a goal, it's hard to recommend anything specific. Some good pointers - Khan Academy is great because it covers a lot of material at school and some at college level so when you find that you have a gap you can always drop back a little and learn about stuff from school that you've forgotten. The explanations are very accessible and it's a great resource for re-learning stuff. - MIT Opencourseware has courses for university-level mathematics. This is if you want to learn things more rigorously and the material is a bit more advanced obviously. Watch the lectures, read the textbooks, do the exercises. It's free world-class education. And once you have a foundation, you can always grab a textbook on a topic you want to go even deeper in. - Youtube math channels like 3blue1brown are wonderful. I don't think they're for learning really but for exposing you to new ideas, giving you a different perspective on things or just allowing you to enjoy a nice explanation. It's infotainment.