with a throw of 3 dice, what is the probability of getting a 9 or an 11?

The answer is 52/216

Here is the solution posted

I am having really great difficulty in understanding what all the table parameters mean. I also don't know how to get those values on the table. maybe you can guide me?

= sum of outcomes in dice 1 and dice 2

= number of permutations in

= outcome of dice 3 to make 9 or 11

= Number of permutations each of

= multiplying both

I have a background knowledge on permutation which is nPr where n = total ways , r = number of ways the total can be permutated