Decided to start learning discrete mathematics using this lovely set of lecture notes recommended by https://teachyourselfcs.com/. I've never done maths beyond high school, and while some things the author writes make sense, at other times I feel like I'm clinging on for dear life to a sentence which is presumably patently obvious, like "We know that 2^3 = 8 < 10, and hence 2^99 < 10^33". That took me five goes to work out!