The only explanation

My calculator is possessed. There's no other conceivable explanation for why it would suddenly give me an error message instead of doing a calculation that it's done successfully close to 100 times this semester. That would also explain why all the answers I'm getting make no sense. Of course, Erin's calculator seems to be similarly afflicted. It must be a room thing. Sigh. I'm exhausted, I have three more exams and a paper and none of these practice problems are fucking working the way they should. Shit. I'm going to fail tomorrow, barring some major curveing on the professor's part. And you know what else? I don't even care anymore.