Carnegie Mellon University
March 23, 2020

Po-Shen Loh Provides Free Daily Math Lessons

By Emily Payne

Jocelyn Duffy
  • Mellon College of Science
  • 412-268-9982

Associate Professor of Mathematical Sciences Po-Shen Loh invites you to "Ask Math Anything." Every day, Loh streams live on YouTube to give what he likes to call "mathematician office hours," amid school closures brought on by the novel coronavirus (COVID-19) pandemic.

"As soon as I heard about COVID-19 spreading across the world, I started to do my own calculations of how much this would impact our lives," Loh said. He realized that not only would we be home for a long time but many people would be out of school, too. "I wondered what I could do." 

During the 60-minute live shows, Loh interactively answers math questions posted by the audience in the chat and improvises mini-lessons around all different areas of mathematical reasoning. Loh tries to pick out the most mathematically interesting questions that don't require prerequisite knowledge.

He wants the show to welcome anyone who is interested in math. He also doesn't want the lessons to resemble a math class.

"I don't want to replace teachers," Loh added. "This is not a math class to teach you math techniques." Instead he wants viewers to think about math in context. "My goal is to have a freewheeling chat to show how concepts interact in math and how those concepts interact with the real world," Loh said.

In a recent episode, Loh began the show by answering "How do you generate true randomness?" Loh liked this question because not only do very few people get to appreciate true randomness but he was excited to talk about the many practical applications of randomness.

He touched on areas of quantum mechanics, the fallibility of computer random number generators, and even how randomness can apply to video game development. He also showed a few number tricks for finding randomness among numbers 0-100.

His entire 15-minute response was improvised, something he views as a personal challenge. "Instead of preparing math lessons to teach you like a teacher, I want to improvise a story," Loh said.

Loh credits his ability to do this to his experience taking improv classes and teaching Carnegie Mellon University's Putnam course. After teaching this course for five years, he noticed a distinct change in his teaching style.  

"My goal is to have a freewheeling chat to show how concepts interact in math and how those concepts interact with the real world."

The Putnam course teaches students how to invent their own ways to solve a problem. There are no scripted lectures, no formulaic problem-solving steps. Instead, Loh gives students a problem and asks them to brainstorm concepts and ideas that might help solve it.

Students could suddenly invoke any area of math to try to solve these challenging problems, and he found himself needing to explain wide-ranging concepts of math up to an undergraduate sophomore level on the spot, without notes or preparation.

"Having students throw ideas at me from all different areas of math five days a week for five years, I got practice thinking on my feet, trying to explain any topic that might come up."

This is what made "Ask Math Anything" a natural response to help mitigate the social and educational setbacks during COVID-19. "It only takes me an hour each day to turn on the camera and start answering questions from around America and the world."