Hi, glad to hear from you. It is helpful to remember that the order of a combination matters. If the order is A, B, C, there is no one before A. So A's marginal contribution is v(A) - v(0). Let's go through Table (A.1) to compute Ann's Shapley value. There are 6 permutations in the column "Combination". The third combination "B, A, C" says Ann enters after B, and C enters after A. Ann's marginal contribution to the union of B and A is v(B, A) - v(B). C is after A so it does not impact A. Let's look at the last combination "C, B, A". Before Ann enters, there are already C and B. So Ann's marginal contribution is v(C,B,A) - v(C, B). I hope this helps.