6 birds were sitting on the fence. 4 more birds and 8 more storks came to join them. How many birds are sitting on the fence?
There are $x$ birds sitting on the fence. 
If 4 more birds come, then there are $x+4$ birds sitting on the fence. 
If 8 more storks come, then there are $x+8$ storks sitting on the fence. 
So, we need to solve the equation:
$$x+4+8=6 \Rightarrow x=6-4-8=-2$$

There are no birds sitting on the fence.