XI'AN — Wearing a whistle around his neck, Zhu Xiaolong, 35, was coaching 14 students at a primary school in Northwest China's Shaanxi province when the school bell loudly rang. Swiftly returning to the classroom, he grabbed a ruler and switched to his other role.

"Now who can tell me the formula used to calculate the area of a circle?" asked Zhu, who is also a math teacher at the Weifeng Central School in the Huyi district of Xi'an, Shaanxi's capital.

Speaking about his dual role, Zhu said, "I want to become the best soccer coach among math teachers, and the best math teacher among soccer coaches."

An ardent soccer fan since childhood, over the last nine years he has coached more than 200 children in the sport and guided the school team to victory in the district league on three occasions.

In 2013, when several clubs were launched at the school, the idea of starting a soccer club crossed his mind. The principal approved his proposal, marking the inception of the first soccer club in Huyi district, attracting 13 students.

The school is located at the foot of Qinling Mountain and many rural children had never touched a soccer ball before, said Wang Shangwei, principal of the school. So, Zhu had to start from scratch.

"I meticulously plan each day, making the most of every minute," Zhu said. "While striving to improve the quality of math teaching, I also organize training sessions for the soccer club at noon and during class breaks."

Many of the students didn't know anything about soccer, let alone the rules of the sport. They ran haphazardly with the ball, unaware of what constituted an offside or a foul. Zhu learned the rules and regulations of the sport by watching videos online, before gradually imparting them to his students.

Slowly, the club began to expand. Initially, Zhu was the sole player on the field during class breaks, but over time, more and more children joined him.

Seeing the growing passion for soccer among its students, the school included the sport in its physical education curriculum. "We also enhanced the soccer coaching techniques, and now it has become one of the most popular sports among our students," Wang said.

In 2016, Zhu led the school team to participate in the inaugural Huyi district school soccer competition. Despite securing three consecutive victories, they faced a heartbreaking defeat in a crucial group match, ending their journey in the qualifying round.

The following year Zhu took his team back to the event and emerged victorious. As champions, they represented the district in the city league.

He vividly remembers the day of their final group match. "It was June 16 and we were playing in torrential rain. Despite the adverse weather, our children fought until the last minute, ultimately defeating their opponents."

The performance of Zhu's club has consistently improved. In 2020, they finished third in their group in the city-level league, and in 2021, they were ranked sixth among all teams in the city.

He has also dedicated considerable effort to enhancing his mathematics teaching. Last year, he was recognized as a primary school math teaching expert in Xi'an.

"As a math teacher, I had never thought that I could go this far in soccer coaching," Zhu said. "No matter mathematics or soccer, my final goal was to help my students, so they can be healthy both physically and mentally, and enjoy happiness at school."