the fx-19 has the chunky old-style build from 1976 slightly
evolved from the baroque style of the fx-101
but appears functionally identical to the later fx-29,
calculations appear to give the same answers as well.
the function set and style are evolved from the earlier fx-101,
offering fractions, gradians mode, statistics and also the luxury of a
10^x button. the keys and case are more rounded but the layout is similar.
taking 4 `AA' cells rather than two, it has a slightly larger and
clearer 8 digit vacuum display. although according to the label claims to
draw only 0.35W instead of the 29's 0.75W.