Hello Tim and DJ Omnimaga!
Thank you both for your replies.


Tim, I do understand that limited precision calculations have, well, limited precision and will be subjected to imprecision when dealing with recurring decimals and such. That explains the 0.999... answer in Home mode as you said. And now I see how students would interpret the result and learn with it.
However, how can CAS do infinite precision calculations in a limited precision calculator?

CAS gives 1 in both exact and aproximate answer modes, even when I "shift+Enter" the expression to calculate the aproximate answer first, so it doesn't seem to use the exact result as base for the aproximate one. 
How does it achieve 1 then?


I did look up the 1/0 answer in WolframAlpha after my post and did some research in complex infinities. It is a rather interesting subject, but complicated enough to support the "undefined" category when dealing with common math.


Thank you again for your comprehensive reply. Now I can appreciate my Prime even more after learning its philosophies. And, of course, brag a bit about it with my TI-owner friends


GHM