i was following Robb Jones ip and subnetting workbook v2.0 , there the instructor has used number of subnets = 2^n
i solved al the problems
later while looking for books on networks i found subnetting workbook v1.1 by Robb Jones , the same producer, here he was using 2^n-2 for number of subnets .
now i am in total confusion , did some reseach few minutes back again this blog has also used 2^n-2 for subnets , link :- https://www.techrepublic.com/article/subnetting-a-class-c-network-address/
according to latest books and comptia network+ , everyone is using 2^n for determining number of subnets ,, which one is the correct formulae plz help me