To divide the displayed number by another, press this button and then enter the other number.

To multiply the displayed number with another, press this button and then enter the other number.

To subtract a number from the one displayed, press this button and then enter the other number.

To add the displayed number to another, press this button and then enter the other number.

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

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

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

This setting has no meaning in binary mode.