4 bits adder with Carry bit
Allows you to perform an addition operation between two binary values encoded on 4 bits each (therefore from 0 to F).
The Carry bit allows you to know if there was an overflow during the addition operation. Note that it is possible to chain the adders to perform operations over 8, 12, 16 bits.
The 4-bit adder is essential for making a rudimentary ALU (Arithmetic and Logic Unit). It will be one of the essential components if you want to make your own retro-computer.