"What's the weather going to be like?" he asked. She said there was a 20-percent chance of rain. "Twenty percent?" he said. "Last week they said 20 percent, and it didn't rain a drop. I'm not going to take my umbrella. Twenty percent means zero percent." She said, "But the week before that, they said 20 percent and it actually rained all day." He said, "You're right. They're 50 percent with their 20 percent. But I hate carrying that umbrella around. Plus, the last time I took the umbrella, I left it at a restaurant." She said, "Put a rubber band around your finger to help you remember the umbrella." He said, "The last time I did that, I forgot to remove it and my finger got all puffy. I could've lost my finger." She said, "Tie a string around your thumb. That'll remind you to remove the rubber band."