I am having a bit of difficulty with this whole thing, i have the question: You have the network address of 199.154.99.0 and subnet mask of 255.255.255.240. What is the network address of the 6th usable subnet? Now i know the answer is 199.154.99.96 but i have no idea how they got to that. I really need someone to explain it and then i think i will get it. Please help.

You have to understand binary, and exponents before understanding subnetting...if you understand that 240 is equal to 11110000 in binary your making progress....and because it's 4 zeros then 2*n (where n is 4) then 2 to the power of 4 is 16. Now all you have to do is add 16 each time you want a new subnet, for example, 199.154.99.0, then you get 199.154.99.16, the next is 199.154.99.32, the next is 199.154.99.48, the next is 199.154.99.64, the next is 199.154.99.80, and finally 199.154.99.96 Lets say you 255.255.255.248...the binary for 248 is 11111000. That's 3 zeros..so 2*3 is 8. so for 199.154.99.0, then the next is 199.154.99.8, then 199.154.99.16, then 199.154.99.24, etc. That's how it works but you have to know the math.

D, You just explained it better than any other site or tutorial i have read. Thanks so much!!