Michael Byster (born March 5, 1959) is an American mathematician, mental calculator, and math educator. He worked as a commodity trader until he quit his job to devote himself to teaching children his methods. He has spoken to over 10,000 classrooms for free and continues to mentor kids. Mike is able to do many arithmetic problems in his head at very fast speeds. During a study done years ago, Byster was claimed to have one of the fastest mathematical minds in the world.