An aspie student is quite good with mental calculation, but has a habit of looking up into the sky whenever he does his calculations. He is a third-year student in a university, major in Computer Science, and he works part time in a convenient store near his uni. He does not speak much on the job; but he is honest, hard-working, and is well-mannered around the customers. The shop owner likes him.
One day on his shift, the student was tending the cash register, when suddenly the power went out. Without the help of the barcode scanner or the computer, the student utilized his knack on calculations and kept serving the customers, working out each bill after a brief moment of sky-gazing. The shop owner works out the same charges a few times and verifies each one -- the student gets it right every time! The owner is amazed.
Finally, after the last satisfied customer had left, the owner approaches the student, with uncertainty in his voice he asks: "How can you be so accurate just by staring at the sky?"
"Easily", replies the student. "It is just . . ."