"2+2=5" by Radiohead

What is this song talking about lyrically?
It's talking about how the singer just allows things to happen and doesn't think to do anything about it until it is too late. The repeated lines stress the fact that the person has not been "paying attention" to what has been going on until it gets to the part where he wants attention (people to pay attention to him.)

How does the music mirror or help push the message?
The music is wavering throughout the entire time, showing how the person is not paying attention to what is going on. This gives off a confused or wavering imprssion like he doesn't know what to do now that the world has gotten to where it is. The music also sounds vaguely depressed or distressed, which gives the emotion of not being happy with the way things are.

The title is an allusion to 1984...explain the connection.
The government in 1984 controls everything, including the truth and what the past actually was and the main character even says that eventually the government would be able to say that 2+2=5 and no one would be able to say otherwise.