This provides an 8-bit two’s complement adder/subtractor circuit, offering the ability to perform A+B or A-B (where A and B are 8-bit binary numbers). This can be used to experiment with unsigned and signed binary arithmetic, as well as offering a different way to observe and understand binary number systems. This can even be extended to a 9-bit adder circuit, by using the Logic Section of the kit to implement a Full Adder.