The main thing you need to understand in the original question is that the probability of throwing 2-x with a fair pair of dice is 11/36.
From there, you have this portion of all possible throws representing 100% of your region of interest.
Eleven unique outcomes is all you got.
Now, when I tell you "at least one 2 is showing" that will be 100% of the times true. And only one time out of eleven will you be right if you call "the other die" as a 2.