[Davidp00]

>I can tell from personal experience that I only properly understood simpler mathematics when I started learning more complicated one.

That's interesting, I have similar experience. Maybe that just means we didn't learn the original material well enough?

[randcraw]

But the only way to maaster new material is to apply it to something more advanced, rather than just practice it. Rote takes you only so far; you can solve only problems you understand already. But learning new kinds of problems expands your understanding of the limits of the concepts and techniques you already know.

[alejohausner]

One of the commenters to the original article talks about this phenomenon specifically. Each math course you took taught you some ideas or techniques, but those techniques weren't really learned until you used them in the next course. For example, you didn't learn algebra well until you used it in calc 1; calc 1 skills are really cemented in difeq.

https://micromath.wordpress.com/2011/05/17/time-lag-in-learn...