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“This,” says Matthew Carpenter, “is my favorite exercise.” I peer over his shoulder at his laptop screen to see the math problem the fifth grader is pondering. It’s an inverse trigonometric function: cos^-1(1) = ?

Carpenter, a serious-faced 10-year-old wearing a gray T-shirt and an impressive black digital watch, pauses for a second, fidgets, then clicks on “0 degrees.” Presto: The computer tells him that he’s correct. The software then generates another problem, followed by another, and yet another, until he’s nailed 10 in a row in just a few minutes. All told, he’s done an insane 642 inverse trig problems. “It took a while for me to get it,” he admits sheepishly.