A coin has two sides, heads and tails, and if you take 100% divided by two you get 50, you want to know what is the probability it will land on tails TWICE so divide 50 by two and you get 25.
There are an infinite number of such subsets. One of them is the set of real numbers in the interval (7, 8). Perhaps you're thinking "irrational" numbers, as opposed to "integers" or "rational" numbers.
