Let: A = {1,2,3,4,6,7,11) B = {1,3,5,6,8,11} C = {1,2,3,4,5,8,9,10} Find the bitwise: a. A XOR B b. B DIFF C a.) Are we simply looking for numbers in A and not in B as well as numbers in B and not in A which will be ANS: A XOR B will be {2,4,5,7,8} That's correct. A XOR B will not contain 1,3,6,11, because they are in both sets. It includes all the other members, regardless of which of the two sets they are members of. A XOR B means: (A OR B) AND NOT(A AND B) ("exclusive OR") b.) In this case are we looking for what is in B and not in C? B DIFF C ANS: Yes, we take 1,3,5,8 out of B and that leaves {6,11}. It doesn't matter that we can't take 2,4,9,10 out of B because they are already out! :) Edwin