All you need to know about calculating the odds
are fractions. Lets
say you need a flush to beat your opponents straight. If thats the
case, and after the flopp you need 1 more flush card, you do the following.
There are 10 cards left of the same suite in the deck which will ultimately
give you the flush if they catch. there are so far 5 cards revealed to you,
yours and the flop, which leaves 47 cards left. Now for the turn, there
is 10/47 chance of you catching, and if you miss, a 10/46 on the river.
You add those two fractions, and convert them to percentages, which
should give you some what less than 50%. Thats all you need to know
to be able to do all the other calculations in poker .