I gave him the figures and he worked it out fine, and when he got through, he said, putting his pencil on a line, "x equals 78."
"Sure that's right?" I asked.
"Of course it is! It's perfectly plain. I can prove it, too."
But I put my pencil on the one we'd worked just before. "This says 'x equals 90,'" I said.
"Well, but that—" began Bob; and then suddenly he stopped and looked at me as if he was going to chew me all up, and then—he laughed.
"Chet, you're a fraud," he said. "You got me off my guard."
"It's different when you understand it, isn't it?" I said.
"It sure is! And is this the sort of thing that algebra and geometry are?"
"Yep."
"And everything is just as clear and plain as these?" and he pointed to the paper.
"It is if you use your common sense."
"I'm a fool," said Bob.
"I'm with you," said I, with conviction, and we separated at the corner.
