This may or may not belong on meta, but I didn't have a specific math related question so felt it fits within here (meta).
I am a software developer, I have some college algebra under my belt but it was about seven years ago. Math is not one of my strongest subjects (ironically) and I believe I would be a better developer if I improved my knowledge in areas such as algebra, trig, calculus just to name a few.
Where can I start relearning some of the fundamentals of algebra on this site? And also, where can I get started with trig and calculus? When I try to research these topics, it feels like there are large gaps in my understanding of maybe other math fundamentals to these disciplines and therefore I cannot begin to grasp the ideas expressed in questions asked here or even just educational sites teaching these subjects.