The probability of the first card being an ace is 4/52 because there are 4 aces in a deck, but because there is no replacement, the probability for the second card being an ace is 3/51. To find the probability of both happening, you multiply to get 3 × 4 = 12 and 51 × 52 = 2652, which gives you 12/2652 = 2/442 = 1/221, your final answer. I hope this helps!