Wow, they used to be allowed back when I was in high school. It came in super clutch for SAT but much more importantly AP. Our school mandated the original CS CAS and drilled us on how to use it effectively and I got good mileage out of it through high school testing and college.

I lost it at some point and got the version 2 and I would occasionally use it for work. I wish it had USB-C because who has a mini-B cable for charging these days

They let you write python programs as long as it’s from memory though. I wonder what the code golf looks like for a rudimentary python CAS. If you could evaluate the equation without needing to parse it, I bet you could get a lot of mileage out of a black box gradient decent routine. The analog circuit solver I wrote for my nSpire (without CAS) was ~11kB. https://github.com/deckar01/pylacc