I watched the first video. Very engaging speaker who appears to be a polymath. I fear the subject may be too abstract for me, but I intend to watch more of the videos up to the point where I'm not understanding what he's saying.
Yeah, I think it helps to have a bit of background in some of the examples. Having done a bit of coding in Elm made the code examples seem natural. I find I have to stop at times but can usually come back to it ok. So far I'm up to 5.1.
Anyways, keen to see others' recommendations for mathy stuff.