"Step 1: Calculate the the total # of possible flops
given that only 32 cards remain in the deck-
32*31*30/6 = 4,960"

Why divide by 6??

"Step 2: The number of A,x,y or K,x,y flops are 4
(number of Aces and Kings left in the deck)*28*27/2 =
1,512"

Why divide by 2??