The output of the half-adder is a result of 0 or 1 and a carry of 0 or 1. Additional circuits shift the operation to the next binary digit on the left until the entire number has been added.

This is the groundwork for the half adder . The next step is ... (A ^ B)) */ /* The standard adder uses OR for the last 'gate' - this can safely be changed to XOR, which has been done here to ...