A MARTINEZ, HOST:
Good morning. I'm A Martinez. A brother and sister in San Francisco used to run a lemonade stand every summer. Now they mine cryptocurrency and earn tens of thousands of dollars every month. As 14-year-old Ishaan Thakur told The Dallas Morning News, most kids like to play games on their computer. We like to build them. He and his little sister, Aanya, have dozens of computers able to make billions of calculations every second, and they say that they're saving up for med school. It's MORNING EDITION. Transcript provided by NPR, Copyright NPR.