Amen to that. I also have a HP48s, which I still use. Back when I was in school, I sometimes used it to cheat. To do this, I add to input many formulas or reproduce drawings, or write programs to perform some calculations (atomic physics comes to my mind). But in the process of doing that, you learn a lot. Eventually, you don't have to cheat anymore because you know pretty well the subject. And even if you didn't work enough to learn all you were supposed to, you've still learnt some of it. This makes a huge difference compared to, say, using a smartphone to browse the internet and find your answers.