I am new to the concepts of using adders to add numbers but I tried using the definitions which I understood as given two binary digits A, B the full adder takes three inputs A, B, C where C acts as a control bit or a carry bit, gives the SUM= (A XOR B), C=A.B, where . is the AND operator. NOw to find the sum of numbers let's say 2 and 6, first, I write the binary representation of both i.e 010 and 110, since they are 3-bit numbers I use 3 full adders and proceed as follows
a0 b0 c0 S0 C
0 0 0 0 0
1 1 0 0 1
0 1 1 0 0
So my ouput string becomes '000' but it should have been '1000' i.e 8, what am i missing can somebody explain.