I'm studying Lammle's Fifth edition study guide for the CCNA and see the subject of ip subnet-zero and now to find the number of subents it is 2 to the power of 2 for the number of bits in your subnet mask depending on your class.
It is no longer the 2 to the above -2 to find the number of subnets available.
It is easy to figure both ways as you simply no longer subtract, however, does the CCNA test for its subnet questions tell you if ip subnet-zero is enabled or do you assume that it is now on.
I really don't want to blow the test on the subnet calcs.