My Robot Teacher Made a Mistake

Our school acquired a robot teacher for mathematics, and everyone was initially intimidated — robots are supposed to be perfect, after all. But on the third day, it added two and two and announced the answer was five. The room fell completely silent. The robot examined its own calculation, then looked at us. "I appear to have made an error," it said, "which is statistically improbable, and also rather human of me." It then awarded everyone full marks for their...