Answer:
Zero.
Explanation:
Well, assuming that the cards are numbered 1, 2, 3, 4 and 5, then the probability of getting 6 is zero, because there's no card with such number.
Remember that a simple probability is a ratio between the possible events and the total number of outcomes. In this case, the total number of outcomes is 5 and the events are zero, because there's no card with 6.