So we are task to create a circuit with the use of the Ic's mentioned that will add from 0-15 and will display the output in a dual 7 segment. Although from what I know the decoder can only display from 0-9 from the 7 segments we will also need to display each inputs making it 3 dual 7 segment displays. But my problem still is the output, how will the decoder of the output display 0-30? What kind of modifications to a special IC to do this?