[cyberax]

My memory was not great either. It's still not that great, so I'm learning Chinese to train it (memorizing Hanzi characters helps).

For me it's outlandish that somebody can forget long division. I literally haven't done it in 20 years, but I've just tried it and I can do it fine.

I guess not using calculator at school helped a lot. My math and physics classes all had arithmetic that could be done mentally, or occasionally on a piece of paper.