Answer: Hello mate!
In a fair die all the number have the same probability; 1/6
The probability of getting a 4 is the sides with the number 4 divided by the total amount of numbers in the dice, this is 1 divided by, the probability is 1/6
The probability o getting a number divisible by 3 is the number of numbers that are divisible by 3 divided by the total amount of numbers in the dice:
The numbers divisible by 3 are 3 and 6, and in the dice, there are 6 numbers in total, so the probability is 2/6 = 1/3