Let the Carry Bit Move the Number Forward
XOR computes the low bit of a two-input sum. AND detects the carry. A full-adder adds the incoming carry, combines the two carry conditions, and sends the result toward the next bit position.
A MUX graph can construct each of those Boolean choices. Repeating the graph across bit positions turns one local operation into an adder of any desired width.
The three-value sequence below keeps the lesson anchored to an executable input pattern before the course moves into a continuous bit stream.