Consider that the event are no mutually exclusive because you can obtain a black card and 2 in one card.
In a standard deck you have 52 cards. There are 26 black cards and 4 cards with number 2.
Consider that in the 26 black cards there are two black cards with number 2.
Then, to get the probability consider that the required result can be obtained for 26 + 2 = 28 cards (26 black cards and two cards with number 2).
The probability is the quotient between the number of options over the number of cards:
Hence, the probability is 0.54