We draw 2 cards from a deck of 52 cards. what is the probability that both are queens?

Use combination
There are 4 queen cards in a deck of 52 cards
Probability = 4C2 / 52C2

I calculate 4C2 first
4C2 = 4! / (2! 2!)
4C2 = (4 × 3 × 2 × 1) / (2 × 1 × 2 × 1)
4C2 = 6

Then I calculate 52C2
52C2 = 52! / (50! 2!)
52C2 = (52 × 51)/2
52C2 = 1.326

Hence, the probability is
Probability = 4C2 / 52C2
Probability = 6/1,326
Probability = 1/221