[eikenberry]

Not going to argue math, but that final statement is a poor way to frame understanding/learning. You can understand something well enough to solve it from memory a few times when in close proximity to the time you learnt it. On the other hand you can understand something well enough to know how to check the references and solve it for the rest of your life.

That is it is better to understand how to solve problems with references than without. You'll forget most you know but once recorded you can't forget. Then you just need to know it exists so you can find it.