1) I'm going to deal to player A all of this player's cards first:
--- it doesn't matter what this player gets on the first card: 12/12
--- there are 8 cards remaining that don't match the first card: 8/11
--- there are 4 cards remaining that don't match the first two cards: 4/10
Now, for player B:
--- it doesn't matter what this player gets on the first card: 9/9
--- there are 6 cards remaining that don't match the first card: 6/8
--- there are 3 cards remaining that don't match the first two cards: 3/7
Now, for player C:
--- it doesn't matter what this player gets on the first card: 6/6
--- there are 4 cards remaining that don't match the first card: 4/5
--- there are 2 cards remaining that don't match the first two cards: 2/4
Now, for player D:
--- it doesn't matter what this player gets on the first card: 3/3
--- it doesn't matter what this player gets on the second card: 2/2
--- there is only one card left: 1/1
Multiplying these together: 0.0374