here is a classic from the early 80's. by the time this
model came out casio had pretty much finalised the content of a
scientific calculator; trigs, fractions, stats, physics constants and
number bases. also extras like combinations and permutations. it is not
programmable as was positioned at a mid price range. the screen is
clear and 10+2 (11 internal digits) and the plastic buttons operate
nicely with sensible spacing. the unit is powered by two g12 batteries
and comes in the ubiquitous flip over wallet style case.
later remakes like the fx570d added more
constants, a delete key, complex numbers and fancy annunciators, but i
still prefer the keys on these older models to the new ones.

