74LS139 Dual 1-of-4 Decoder/ Demultiplexer in Pakistan

These full adders perform the addition of two 4-bit binary
numbers. The sum (R) outputs are provided for each bit and
the resultant carry (C4) is obtained from the fourth bit.
These adders feature a full internal look ahead across all four
bits. This provides the system designer with a partial lookahead
performance at the economy and reduced package
count of a ripple-carry implementation.