“Check it for yourself, Congressman.”

The congressman took out his pocket computer, nudged the milled edges twice, looked at its face as it lay there in the palm of his hand, and put it back. He said, “Is this the gift you brought us here to demonstrate. An illusionist?”

“More than that, sir. Aub has memorized a few operations and with them he computes on paper.”

“A paper computer?” said the general. He looked pained.

“No, sir,” said Shuman patiently. “Not a paper computer. Simply a sheet of paper. General, would you be so kind as to suggest a number?”

“Seventeen,” said the general.

“And you, Congressman?”

“Twenty-three.”

“Good! Aub, multiply those numbers and please show the gentlemen your manner of doing it.”

“Yes, Programmer,” said Aub, ducking his head. He fished a small pad out of one shirt pocket and an artist’s hairline stylus out of the other. His forehead corrugated as he made painstaking marks on the paper.

General Weider interrupted him sharply. “Let’s see that.”

Aub passed him the paper, and Weider said, “Well, it looks like the figure seventeen.”

Congressman Brant nodded and said, “So it does, but I suppose anyone can copy figures off a computer. I think I could make a passable seventeen myself, even without practice.”

“If you will let Aub continue, gentlemen,” said Shuman without heat.

Aub continued, his hand trembling a little. Finally he said in a low voice, “The answer is three hundred and ninety-one.”

Congressman Brant took out his computer a second time and nicked it, “By Godfrey, so it is. How did he guess?”

“No guess, Congressman,” said Shuman. “He computed that result. He did it on this sheet of paper.”

“Humbug,” said the general impatiently. “A computer is one thing and marks on paper are another.”

“Explain, Aub,” said Shuman.