Carry look ahead Adder:  Carry look-ahead adder utilizes the logic gates to look at the lower order bits of augmend and addend to see if a higher order carry is to be generated or not.  Carry look-ahead uses the two concepts of carry propagate and carry generate functions. This th adder uses the following equations for i  stage: Carry propagate Pi=Ai Bi Carry generate  Gi=Ai.Bi Sum Si= Pi Ci Carry Ci+1=Gi+Pi.Ci The circuit diagram of  3-bit Carry Look-Ahead Adder is shown in the following figure: