"2 + 2 = 5" // Radiohead

• The lyrics seem to be describing a society in which the accepted truth isn't necessarily what is actually true. The speaker is very frustrated with this and wants the audience - or the rest of his society - to stop allowing this injustice; he wants them to "pay attention".
• The music sounds somewhat menacing and angry, and that helps to push the lyrical themes.
• This song is a reference to 1984 in that the citizens of Oceania are forced to believe whatever they are told by the authoritarian government even if they are told that "2 + 2 = 5". The government in 1984 decides the truth just as the speaker describes in the song.