--- On Wed, 5/20/09, Ethan Dicks <ethan.dicks at gmail.com> wrote:
  Hmm... that's a promising lead.  I should go surf
some
 C= calculator
 sites (I just have one Minuteman that mostly works but
 individual keys
 are somewhat sketchy, and it does want four "N"
 cells). 
The calculator I mentioned was apparently the Minuteman 6:
http://www.vintage-technology.info/pages/calculators/commodore/comin6.htm
I owned one of these as a kid.
--Bill