Terminated: unknown
An interesting key is the DR key. It undoes the last number key that was pressed. It works only once so it can only undo one keypress. Since I don’t have this calculator’s manual I am at a loss to what DR is an abbreviation for. Anyone? Digit Reverse?
Even though this is a scientific calculator it does not have the capability to work with exponential numbers. The highest value it can cope with therefore is "99999999", the lowest its negative value.
The CE/c key is awkwardly placed in my opinion. When playing with this calculator I have pressed it numerous times expecting the "=" key in that exact location.
The leftmost digit is used for displaying the sign of a number and is used for indicating an error condition by lighting up the three top digits displaying an upside down "u".
Calculations are automatically repeated when the =/K key is pressed.
The workings of the xy key might be puzzling to users of this calculator. When you enter a (positive) number and press the xy key an intermediate result is shown, being the natural log "ln" of the number entered. To obtain its power enter the value for y and press the =/K key. My guess is that this calculator uses this formula:
xy = e(y · ln x)
This works nicely for positive values of x but will result in an
error when x is zero or less. Not a big problem because powers of negavive
numbers behave counter intuitive anyway (producing non-complex results
only for integer values of y or fractional values of y with an odd
denominator).
On the top-right there is a slider to select the current angular mode.