Casio fx-5800P

[tomisan]

Don't underestimate this little calculator, except for graphics and string manipulations, the Casio Basic included has most of the features - including Getkey and Locate - found in the more expensive models. It has even a few features lacking from the graphics calculators:

To prompt for input, the normal way is:
"N"?-->N
Will display N? and store the input in variable N.

Casio fx-5800P also allows this:
"N"?N
Will display N? but also shows the variable N. If no change, then you can press EXE right away. Very handy!

It has a FILE key on the keyboard making it easy to run any program outside Program Mode. With my Casio fx-CG50 I have to switch to Linear Mode, then retrieve the Prog command from the catalog and finally type the program name on the keyboard enclosed in quotation marks. Very awkward.

Often used programs and formulas can also be added to a Favourite List, another useful feature.

I also like the CALC and SOLVE keys available to quickly enter an equation and solve for any variable:
E.g. BMI=weight (kg)/height (m)^2
Type B-W/H^2, press SOLVE key, enter W and H and press SOLVE again. Done!

The single AAA battery lasts one year if calculator is used 1 hour a day. It draws only 0.12W.

The biggest drawback is that it might be too slow for some. The same prime factorization program used on both the fx-5800P and fx-CG50 gives me:
N=6666666667 (19 x 1627 x 215659)
fx-5800P: 25.4 s
fx-CG50: 2.5 s

The calculator was introduced in 2007, I really hope Casio could upgrade it with a faster processor, more memory and a PC-link.