The most essential math you should know as a web developer is high-school-level math (algebra, geometry, and trigonometry) along with discrete math (logic, set theory, combinatorics, and graph theory are the most important topics). I just wrote another post previously on resources for learning discrete math: Frustration from a low quality computer science degree
Not math per se, but you should also learn at least a little about hexadecimal numbers because those come up in CSS.
There are many reasons why C is still part of most CS programs—but basically, it helps gain understanding of how the computer and memory works (which is important for coding in any language). And although it’s old, the knowledge that’s gained from using it is translatable to other newer languages.
Some other learning resources that I’d recommend to supplement FCC are these courses:
- CS50X by Harvard on edX (I’d recommend doing this before starting FCC—it’s basically an “Intro to CS”)
- The Web Developer Bootcamp by Colt Steele on Udemy
- Git a Web Developer Job by Brad Schiff on Udemy