To evaluate the current calculation, press this button.

To delete the last digit entered, press this button.

To clear the display, press this button.

To clear the current calculation and the display, press this button.

To perform a bitwise exclusive-OR of the displayed number with another, press this button and then enter the other number.

To perform a bitwise NOT of the displayed number, press this button.

To measure angles in radians rather than degress, press this button. 

This setting has no meaning in binary mode.