CAS: 0/0 is undefined, however 1/0 is infinite?

[parisse]

to sasa: a CAS is a computer algebra system, not a math teacher. Before high school, you don't really need a CAS, except for tasks like checking expand/factor. And it's the job of the math teacher to explain that you must sometimes wait a couple of years before you can understand everything, and in the meantime there is a difference between what you learn and what a professional CAS does (same for 1/0 or sqrt(-1)). The same applies for all sciences.