13. There are two bags, $A$ and $B$. Bag $A$ contains 6 cards, one of which is labeled 0, two are labeled 1, and three are labeled 2; Bag $B$ contains 7 cards, four of which are labeled 0, one is labeled 1, and two are labeled 2. One card is drawn from bag $A$ and two cards are drawn from bag $B$, making a total of three cards. Find
(1) the probability that all three cards drawn are 0;
(2) the probability that the product of the numbers on the three cards is 4.
13. (1) $P=\frac{C_{1} C_{4}^{2}}{C_{6} C_{7}^{3}}=\frac{1}{21}$;
(2) $P=\frac{C_{2}^{2} C_{2}^{2}+C_{3}^{1} C_{1} C_{2}^{2}}{C_{6} C_{3}^{3}}=\frac{4}{63}$.