In IT exams you will often have one of two types of subnetting questions.   The first type you have just seen.  You have been given a certain network number and subnet mask and you need to determine which subnet the IP address is in.  The second type of question is to design a subnet mask to give a customer a certain number of hosts and a certain number of subnets.

We will shorten the five steps down.  It does help though, to go through them to answer any type of subnetting question.