In a standard deck of card, there are 4 sixes, and 52 cards.
That fact means that the chance of being dealt any six will be 4 divided by 52, or 1 in 13.
In the case of any spade, the situation is different, since there are 13 spades in a deck.
That fact means that the chance of being dealt any spade will be 13 divided by 52, or 1 in 4.