Well there is only one 3 of spades card in a deck, so the probability of drawing that is 1/52
If you then draw a 4 of spades (if that's the question) that's a 1/51 possibility.
The possibility of choosing randomly a 3rd of spades and then a 4th of spades is 1/52*1/51 or 1/2652.
I hope this answers your question :)
