CASIO fx-4000P scientific calculator from 1986

[Dave Britten]

(09-26-2018 01:25 PM)burkhard Wrote:  When in college with my 15C in the late 1980s, I remember a few friends with Casios like this or very close. I liked them a lot except for the cardinal sins of being non-RPN and rather mushy non-click buttons. But, a decent display and very pocketable!

I must restrain myself from branching my collection into old Casios as well. Stop. Stop now.

The good news is that most Casios are really cheap compared to just about any HP. You can probably get a whole sack full of them for the cost of one nice 15C or 42S!

Also, the array-style memory addressing of their older models (up through what Wikipedia calls the 1st generation of graphing models) makes it super easy to create a MISO-style solver using the secant method. Thus you can do very user-friendly - and accurate - TVM on a 4000P, and still have a few hundred bytes left over for an amort routine. When looking at other models, if you see "Defm" somewhere on the keyboard or in the Mode key reference, it probably functions the same way. Later models added list variables but removed the ability to address A-Z variables with array indexes/relative offsets.