You roll a 6 sided die. find the probability of the event that you roll a number less that 4

Explanation:

The list of items we want to land on are {1,2,3} which are all less than 4. There are A = 3 items in this set.

The list of possible outcomes are {1,2,3,4,5,6}. There are B = 6 total outcomes.

Divide the values of A and B to get A/B = 3/6 = 1/2.