Q- Implement the following equations using only Half Adder circuits.
D= A XOR B XOR C
E = A’BC + AB’C
F = ABC’ + (A’+B’) C
G= ABC
Ans: We know the equations for Half Adder are
S = A xor B and C = AB
And can be represented as follow:

We have 3 inputs A, B, C and we need D= A xor B xor C
So we connect 2 HA as below to get D

And the other output of 2nd adder is (A XOR B) C = A’BC+ AB’C which is actually E
Now we need F = ABC’ + (A’ + B’) C
which can be written as F = AB C’ + (AB)’ C = (AB) XOR C hence connect carry output of 1st adder (which is AB) with input C as follow:
And we get G= ABC at the other end.