Two cards are dealt from a standard deck. What is the probability that they form a pair?

For the first pick, the person can choose any card from the given 52 cards. Then, whatever number the card shows, there remain 3 cards of the same rank in the deck. So, for both the cards to be of the same rank, the person has to choose the second card from these 3 remaining cards.

Therefore, the probability that these two cards form a pair is:

2