text: 198.23.100.0\nFirst of all its not an IP address, it a network id. An IP address can't have 0 or 255 as the last digit. If its 0 then its network id and if its 255 then it broadcast ip.\nNow "198" i.e class C. Hence first three octets for network and 1 octet for host.\n5 subnets....borrow 3 bits from host portion. So that 2*3 = 8. \ni.e you will get 8 subnets out of which 6 are useful and since you require 5 so this will work.\nclear up your concepts.\n\nregards