The subnet id identifies which smaller network within a larger network (the subnetted network) the packet should be delivered to. The subnet id is part of the extended network prefix which is used for routing.
The subnet mask separates the network id from the client id in the IP address for a sender or receiver.
Since you haven't given a starting network address or subnet mask, impossible to say.
The subnet mask would be 255.255.255.0
no
A subnet mask is used for this purpose.
subnet mask
because that is the last number of the subnet. the last number in a subnet is used as the broadcast domain. the first number is also not usable. an example would be: id 192.168.20.XX subnet 0f 255.255.255.128 192.168.20.0 and 192.168.20.127 may not be used and 192.168.20.128 starts the next subnet making 192.168.20.128 and 192.168.20.255 not usable
Subnet ID
Subnet mask defines our network bit . If we are using a single network then all computers should have same subnet mask as well as the ip address, that belongs to the same network id.
Since this is a class C address the subnet mask for the default would be 255.255.255.0. Other values could be:255.255.255.128 - 255.255.255.252
3 octet
You can't find the gateway or any other address in a subnet mask; the subnet mask is used to separate the parts of an address - the network id part and the host id part. Look at other settings for the gateway, such as ipconfig or ifconfig