Learning stuff that doesn’t help in work(calculus is not helpful for 99% of software engineering) is really hard if you don’t base it in reality I find. Maybe it’s just me but I would never read a text book for fun so suggesting learning by reading a text book seems crazy. Calculus can be fun and interesting but the teacher has to actively try to make it so. The learning will take longer but you’re more likely to see it through and I think it’s more likely to stick long term too.
I learned way more reading crafting interpreters than I did in my compiler class for example.
That’s interesting because I can’t imagine learning a subject without a textbook. I have a hard time believing another medium would have the depth and density to get all the points across. Although it does depend on the subject matter and one’s learning goals.
But I also do read textbooks for fun… Now that I have a few decades of experience in a lot of these subjects I get way more out of the books. And I can start to understand more of the meta information. Like, of all the things the author could’ve used as an example, why did they pick that. Also, it’s hugely interesting for me to look at the homework problems and theorize why this particular problem was picked. Especially fun for electrical engineering books. But ya, I’m weird like that.