The ALU is the chip that's responsible for performing all the calculations this processor can do. It's far too complex to build all in one go, however, so we have to break it down into component parts.
Below is a list of all the parts that we need to make. They have to be done in order, because each one builds on the one before! Make sure you have a multiplexer built first, because we will need this!
Once you are finished, you can return to the CPU.