Terminated: unknown
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.
The chip used in this calculator knows hexadecimal stuff as well. Although hexadecimal functions are not available on the keyboard, sometimes (when you hold your hand over its solar cell just long enough to have the calculator software go weird) its hex mode would be invoked and hexadecimal calculations were possible. CASIO probably designed one chip for multiple calculators, and in this one the hexadecimal functions are inhibited.
Oh and in case CASIO reads this, I still receive e-mails of people asking if I know where to buy an fx-98. People really like this calculator, as I do, and there’s probably still a nice market for a scientific calculator this small.
This calculator, together with another CASIO model, the CASIO FX-602P are the two calculators most prominent in the "Please sell me one" e-mails I receive. And no, neither one is for sale :-).