4 aces in a deck
 52 cards
 you have a 4/52 reduced to 1/13 probability of picking an ace.
 without replacing it there would be 51 cards left and 3 aces
 so second probability of picking an ace is 3/51 reduced to 1/17
 the probability of doing both = 1/13 x 1/17 = 1/221