In all senses, it is a complete victory for 89.

Program, running speed, scalability

There's absolutely nothing wrong with college.

I have used both the calculators you mentioned. CX is light and portable, but you have to learn economy, using 89, more than software.

If the budget is sufficient, it is recommended to start with HP Prime ... a better calculator, which is faster than CX, about $ 125. It is said that Taobao also has some purchasing services. However, because it is a new version of the machine, there are some bugs and some imperfections (such as Gamma graphics), but it is enough for daily use.

Hp Prime interface:

CX usage chart:

TI89 usage diagram:

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I wish you a happy learning

P.S. himself is the developer of 89 software.