To type the four binary digits '0001' representing the hexadecimal digit '1', press this button.

To type the four binary digits '0011' representing the hexadecimal digit '3', press this button.

To type the four binary digits '0110' representing the hexadecimal digit '6', press this button.

To type the four binary digits '1001' representing the hexadecimal digit '9', press this button.

To type the four binary digits '1100' representing the hexadecimal digit 'C', press this button.

To type the four binary digits '1111' representing the hexadecimal digit 'F', press this button.

The light on at the top left of this button indicates that the calculator is currently in binary mode.