Introduced: ca. 1980
This is a scientific calculator similar to the other Casio models.
This one however had one big advantage: the Fraction-key. With
this key it was possible to input fractions, and fractions stay
fractions as long as you perform a particular subset of operations
This calculator (as do many other Casio scientific calculators) uses one and the same key for both the constant π as well as exponents. This works as follows. When you first enter digits, the "EXP"-key will enable you to enter the numbers exponent, otherwise it will enter the constant π.
When I got this calculator it was broken. Literally, the PCB was in halves. I plated them together and fixed the missing print tracks using coil-wire. And it still works great.
©2009 Ernst Mulder