7. Multibit Addition

A circuit for adding two 4-bit binary numbers:

So far we explored a one-bit full adder.

To add multiple binary bits together, we must include a possible carry over from the lower order of magnitude, and send it as an input carry to the next higher order of magnitude bit.

Multibit addition requires full adders with carry lines to be cascaded (chained together.)

See also: binary subtraction article.