Teaching kids real math with computers/calculators

[Csaba Tizedes]

Hi, I want to teach programming my kids using Processing (later Java and after then Android programming, because I hope they will be billionaire programmers when they will grows up - and they will buy me a lake with a little wooden house with superb internet access )

So, paralelly with this I want to teach calculator programming, and they can understand the limitations and they can solve programming examples on a small system.

Which kind of calculator is best for this purpose?!

Any manufacturer acceptable. The availability, lowest price important and remember, they are kids, therefore they will throw it into their bags, into the corner, spill with water when use it. Maybe dig it in the garden. therefore the 71B or 41CX is not suitable.

I have an idea, the SENCOR has very good clones of CASIO calculators which are programmable (SENCOR SEC103 == CASIO fx-3650P, but the price is 1/4 of the CASIO).

Any idea?