So this is embarassing: I work in HCI, and I know next to nothing about math.
When I was younger, I had a lot of problems. Ended up in a reform school, and they weren't very focused on education.
Fast forward ten years. I've done a lot of self learning... mostly statistics, but there are huge gaps in my knowledge.
Too often in my career, I've decided on a project or course of study based on my math skills rather than my passions.
The problem is, I don't even know where or how to begin. I don't know what I don't know. And whenever I try to look up a specific concept (say, the Wikipedia page on Calculus) there's so much more that I don't know that the gulf of execution is so great I end up just giving up.
Does anyone know of a good online resource to sort of start at the beginning and work my way up?
(For example, I used to also hate learning foreign languages, but discovered Duolingo and have been working on learning German every since. And it's actually kind of fun!)
Khan Academy (https://www.khanacademy.org/) has great resources for all levels of maths up until the first year of university - easily the friendliest and most comprehensive set of classes and topics for maths until that level
MIT Open Courseware (http://ocw.mit.edu/courses/find-by-topic/#cat=mathematics) has many courses that you can pick from and start to learn from. For these it doesn't hurt to see what textbooks they're using (if any) and purchasing them and going through the problem sets yourself.
The great thing about maths, is that until you get to the very high levels, many problems can be checked against pre-made answers.
Hope this helps!