SINGAPORE — On the second floor of a Singapore shopping center, five boys and two girls sat in a small room with the blinds drawn, a whiteboard the only object on the lime-green walls.

Jordan Goh, 12, who began receiving after-school tutoring two years ago, went up to the board to answer a math problem about time and distance, while Dr. Zhong Rui Wen, the founder of the Raffles EduHub, a tutoring center, gave pointers from the back of the room.

“This place, it has been helping me a lot,” said Jordan, who attends the center three afternoons a week. “It drills me on stuff that I don’t understand.”

Every week, about 150 children attend this center, just a handful of the many students taking private tutoring across Singapore, where attending extra lessons after school has become the norm.