If you are given the ipv4 address 1000 0001 1000 1101 1100 1100 , what is that address in dotted decimal notation

The answer is: 

129.141.12.207 

Here is the trick, this is very important.

for every decimal, there needs to be 8 binary characters. 

for example, the problem you provided, you convert:

10000001.10001101.00001100.11001111 

into decimal, you get my answer. 

129.141.12.207

there are binary to decimal calculators all over the web. I think I am now going to make a binary to dotted decimal calculator on my tech blog. 

Hope this helped!!!

Kpa - known-plaintext attack