An unbiased die is thrown. What is the probability of getting:
a number between 3 and 6.

In a single throw of a die we can get any one of the six numbers 1, 2, ..., 6 marked on its six faces. Therefore, the total number of elementary events associated with the random experiment of throwing a die is 6.
The event "Getting a number between 3 and 6" occurs if we obtain either 4 or 5 as an outcome.
$\therefore$ Favourable number of outcomes = 2.
Hence, required probability = $\frac{2}{6}=\frac{1}{3}$.