Its been a while since I have done CIDR and completely forgot when I was going over review questions. How do you CIDR an address without the subnet mask? For example if the problem was CIDR 58.137.15.160-58.137.15.167 how would you go about doing this? Another example would be CIDR 66.240.192.0-66.240.255.255. I'm completely loss and all the youtube videos I find are using the subnet mask to subnet. Any help would be appreciated. thanks