Little Johnny came home from school looking frustrated. His dad noticed right away. “What’s wrong, Johnny?” “I got an F in arithmetic,” Johnny muttered. His dad frowned. “An F? Why? What happened?” “Well,” Johnny began, “the teacher asked me, ‘How much is 2 times 3?’ and I said, ‘6.’” “That’s correct!” his dad said. “Exactly,” Johnny replied. “But then she...