What is the chance of drawing the ace of spades in a single draw from a full deck of cards

There are a total of 52 cards in a deck.
It is divided into 4 suits namely clubs, diamonds, hearts and spades, divided equally among all that is 13 each.
Ace consists of one each diamond, spade, club and hearts.
Number of spade cards = 13
Number of ace cards = 4
But we have already chosen 1 ace card in the 13 spade cards.
Therefor, P{spade or ace} = (13 + 4 - 1)/52
16/52 = 4/13 is the probablity.