Assume a standard deck of 52 cards with four suits.
A straight flush is a when you have a hand of 5 cards, in which the cards are in consecutive order such as A 2 3 4 5 or 10 J Q K A or 6 7 8 9 10.
The possibility of a straight flush is 10*4 divided by Combination(52, 5) when you are dealt a hand of 5 random cards. But what if the first card you draw is the 7 of diamonds? What is the probability of a straight flush then?