[Math] Permutations of 3 digit numbers divisible by 5

Question

I recently had to answer the following permutation question:

How many 3 digit numbers can be formed from the digits 2,3,5,6,7,9 which are divisible by 5 and none of the digits are repeated?

Having not done this kind of algebra since high school could someone break down how this would be calculated. I'm assuming to calculate the number of 3 digit combinations it's half the permutations = 6 x 5 x 4?

Answer 1

Choose $2$ digits from $[2,3,6,7,9]$ and arrange them in any order: $\binom52\cdot2!=20$.