It's all adding up for this wizard of math

Po-Shen Loh is an associate professor of mathematics at Carnegie Mellon University, but in China he is known as the coach of the United States' International Math Olympiad team.

Po-Shen Loh is an associate professor of mathematics at Carnegie Mellon University, but in China he is better known as the national coach of the United States’ International Math Olympiad team.

Under his instruction, the American team won the competition in 2015, 2016 and 2018, ending the losing streak since 1994.

In order to inspire more people’s interest in math, he now comes to China six times a year to give lectures and run a summer camp in cooperation with Tsinghua University. He has also launched free math and science education website

Po-Shen Loh plays dice with a student, guiding him to find out the fact that his dice were different to the normal ones and the rules in dice games.

At the invitation of the Soong Ching Ling School recently, he delivered speeches to students and parents on his experience and ideas of learning math. 

The 36-year-old was the speaker at the school’s fourth Soong Ching Ling Forum, a program that invites scientists, cultural celebrities and industrial leaders to campus to enable students to appreciate their innovative spirit, humanistic thoughts and sense of mission.

During his speech to third and fourth graders and their parents, he spent nearly an hour playing dice with the children, guiding them to find out the fact that his dice were different to the normal ones and the rules in dice games.

He told them he had been thinking about difficult questions since childhood and the special dice were made when he found the number of dots on opposite sides of normal dice made seven. Five is opposite to two, for example, and four the opposite of three.

Loh wanted to see what would happen if that arrangement changed. So he had some special dice made, with six opposite five, one opposite of two and three opposite four.

He found that the dice games was fairer when the dots were arranged in the normal way, but he also found methods to utilize the rules to win in games with dice.

Loh said he loves math as he loves people, challenge and thinking, all of which he could find in math.

“I like staying with people learning math, challenging questions are interesting to me, and thinking about the challenging questions is the most interesting thing,” he said.

Asked by parents whether all students should take courses on Math Olympiad, he said it was more important to make children think and inspire their interest in math rather than telling them some formula to solve questions quickly.

“I think all students should constantly challenge themselves,” he said. “When they can solve all the problems in their textbooks, they can start thinking about more complicated questions, such as the Math Olympiad. Even if they do not do the competition in the future, the habit of thinking about things, which they do not know how to deal with at the beginning, will benefit them throughout their lives. There are tips in competitions, but if you can find the secrets by your own thinking, it’s more interesting and rewarding.”

But he also told teachers and parents they should not blindly have children try knowledge too far from their ability, which he believes is a waste of time, but should pick proper knowledge and keep children making progress gradually.

He said that in America, students have less pressure in school, so they can spend more time on developing mathematical thinking, while Chinese students may spend more time on learning formula and doing a lot of practice.

“But if your goal is not just school application, it’s better to develop children’s ability of thinking,” he said.

“You can still do the Math Olympiad problems, but do not tell them the solutions from the very beginning. Let them think by themselves. When they are capable of thinking, they will succeed not only in math, but also in other subjects.”

Loh said when he faced difficult math problems, he would assess first if the problems were too advanced compared to his ability.

“If it’s not too far away from my ability, I would like to spend more time on thinking to solve it by myself. But if I still cannot solve it, I would check the solution. I would not read through the solution to get the answer directly. I would pick up something from the middle to see if I can get some tips. And then think about the problem again.”

Po-Shen Loh talks to students and parents of Soong Ching Ling School on his experience and ideas of learning math.

Loh said one method to improve children’s interest in math is to have them accompanied by people who love math.

“If the teachers love math and can make math funny, the students will love math too,” he said. “And you’d better turn your students from loving success to loving challenge. If they only want high scores and cannot see the beauty of math, they will not love math.”

He said he wished more people could find the charm of math and using mathematical thinking in life.

“If all the people in the world can think reasonably, we will be able to make more reasonable decisions,” he said.

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