As an alternative for speed running through Khan Academy’s math lessons, there are some online resources specifically aimed for programmers and other fields that could use a fresh primer.

- Calculus for beginners and artists
- Calculus made Easy
- Differentiation for Hackers
- Funny little calculus text
- Maths for programmers (early draft)
- Calculus for beginners (Single page version)
- MIT Calculus textbook
- The Essence of Calculus (YouTube)
- Single variable calculus (YouTube)

Those that have already advanced further, there are lots of resources available:

- A Programmer’s Introduction to Mathematics
- Mathematics for Machine Learning
- Interactive Linear Algebra
- Immersive linear algebra
- Introduction to Mathematical Thinking (Standford)
- Category Theory for programmers
- Category Theory for programmers (YouTube)
- Advanced Calculus

via HN: Mathematics for Programmers [pdf] and HN: Calculus for Beginners and Artists (2003)