Understanding the math and understanding the importance of the mathematical concept are two different things.
Personally, div and curl didn't quite click for me until I took fluid dynamics in my final year. I could do the homework but didn't really get why they were useful until it made sense why "div = 0 always for incompressible fluids".
ok, but my point was that div and curl were taught in 102, not 101 (which you easily could have placed out of). therefore, the reasoning goes, if they were in 101, that must be a hyper 101.
Personally, div and curl didn't quite click for me until I took fluid dynamics in my final year. I could do the homework but didn't really get why they were useful until it made sense why "div = 0 always for incompressible fluids".