the 85m is typical of the ordinary calculators from
casio in the mid 80's. it is only interesting because its not very
interesting, if you see what i mean.
it is ideal for general use. its solar powered without batteries, the
rubberised keys work well and have a tactile feel and the display is
clear, but only 8 digits. although ordinary in most respects, you would be
hard pressed to find a cheap value-for-money unit today that is built to
the same standards. consider what has become of the ti30 line, the ti30xiib.
cheap, yes, but nasty also.
compared to the fx-85v it lacks some features.
the 85v is a bit more advanced, having 2D stats, regression, k-memories,
more buttons, a delete key and rather nice 8+2 display. the 85v model must
be the updated version and this the older one.
one of the problems with
pure solar machines like this one, is that it often powers up in a random
state and unable to calculate. this is remedied by selecting mode 0 and
mode 9, ie setting it back to normality. occasionally, the memory will
also contain garbage or error. the pure solar sharp el-545
has this problem too. it is remedied there by a ca button that acts
to reset the machine.
internally, it is a 10 digit machine, but
to save cost, the display is only 8.