“I design my classes for the average student, like me!”

Sacha Friedli was named this year’s best teacher in EPFL's mathematics section. © Murielle Gerber / 2022 EPFL

Sacha Friedli was named this year’s best teacher in EPFL's mathematics section. © Murielle Gerber / 2022 EPFL

Sacha Friedli hated math at school. But that hasn’t stopped him from being named this year’s best teacher in EPFL's mathematics section, helped along the way by a chance meeting and an extended stay in Brazil.

Some people have such a talent for math that they might as well have been born with a calculator in their hands. And then there’s the rest – those who are average at math, or even "slow and average”. That’s how Sacha Friedli, now a mathematics lecturer at EPFL, would describe himself. He willingly admits that math was his worst nightmare at school. And yet, from practically one day to the next, a teenage Friedli went from being “bottom of the class in math to the top.”

Friedli remembers it like it was yesterday. “I was in my first year of high school in Nyon,” he says. A few weeks after the start of the fall semester, “a new student from German-speaking Switzerland joined our class.” Friedli explains that his new classmate was “really good” at both languages and science. “We took the same bus home, and one evening I asked him to help me with an assignment on continuity in analysis,” he says. Friedli’s classmate got him to understand this key concept. “That moment changed my life. I can still remember exactly where the bus was when it happened!”

“Just like me back in the day”

Although his turnaround in math was both impressive and unexpected, Friedli notes that he didn’t go on to become a mathematical genius. “I’ve kept my ‘average’ side throughout my career,” he says. But despite this, Friedli has been named this year’s best teacher in the mathematics section. In fact, it could be his down-to-earth nature that earned him the award. “I try to design my classes for the average student – so in other words, myself!” he jokes. “This might actually be what makes me a valued teacher.”

Friedli teaches analysis and linear algebra to first-year students, of whom there are “hundreds,” he says. “A handful of them can manage on their own, while at the other extreme, a handful tend to drop out straight away. Then there’s everyone in the middle. They’re just like I was back in the day.” Friedli is keen to stress that “with a little help and motivation, they all have the potential to pass with a good grade.”

Patience above all

Friedli believes that his passion for teaching has developed “naturally and gradually” during his career. “Here at EPFL, I was lucky to have an excellent thesis supervisor, Charles Pfister, who encouraged me to express abstract concepts in a simple, clear way,” he says. Later on, Friedli held a postdoc position at Instituto Nacional de Matemática Pura e Aplicada in Rio de Janeiro. “This experience showed me how important it is to form my own understanding of others’ ideas and to make them my own,” he says. Friedli put these skills to good use when he joined Universidade Federal de Minas Gerais as a professor.

Friedli spent over a decade in Brazil: “For a variety of personal and professional reasons, my year-long stay ended up lasting twelve years,” he says. He returned to EPFL in 2016, this time as a scientist and a lecturer. So how could we describe him as a teacher? “The fact that I struggled at university – I had to repeat my first year, for example – has certainly influenced how I teach,” he says. “I’m very patient, and I constantly tell students I’m available anytime to answer their questions – something they should really take more advantage of!” he says. Similarly, Friedli considers one-on-one contact with his students to be very important. “I fully believe it’s possible, even in classes of over 600 students.”

Images, computer animation and verbiage

Even though he loves math, Friedli is aware that it can seem dry and even daunting as a subject. “I often try to explain concepts using images, computer animation and a fair bit of verbiage, before introducing mathematic symbols,” he says. Friedli has received positive feedback for his computer animations, so he uses them as much as possible in his teaching materials, which are available online. “I get a real kick out of creating these materials for my students!” he says. It makes you wonder who enjoys coming to class more: Friedli or his students. That’s an equation that has yet to be solved.