For three bit additions, full adder is used. First step in designing the full Adder circuit is to have truth table. Before that let see the binary addition rules.

Truth Table for Full Adder

Using the k-map, we can get the optimised Boolean expression for sum and carry.
Boolean expression for sum


Boolean Expression for carry


From the above booleaan expression , we can Implement of sum and carry as shown below

Hello,
I have found this blog quite useful but I have a query:
How many combinational inputs does a 3 bits full adder contain?
Hope for your reply! Thank you.
6 inputs are required for 3 bits full adder