I use Maxima regularly as it was what I was taught at university. It is updated regularly. It's cranky as hell but it works. Sometimes I use the CAS on my calcu

I use Maxima regularly as it was what I was taught at university. It is updated regularly. It's cranky as hell but it works. Sometimes I use the CAS on my calculator, mostly to check my own work, because it hurts less. That's an HP Prime with Giac/Xcas on it.