In the 10 natural numbers of 1,2,3... 9, take any 3 numbers, and find the probability that there are exactly two adjacent numbers in the 3 numbers

In the 10 natural numbers of 1,2,3... 9, take any 3 numbers, and find the probability that there are exactly two adjacent numbers in the 3 numbers

Three at random: 504
There are two adjacent: 6 * 2 + 5 * 6 = 42
42/504=1/12