context: Thirteen-year-old Wei Minzhi arrives in Shuiquan village to substitute for the village's only teacher (Gao Enman) while he is away on family business. When Gao discovers that Wei does not have a high school education and has no special talents, he instructs her to teach by copying his texts onto the board and then making the students copy them into their notebooks; he also tells her not to use more than one piece of chalk per day, because the village is too poor to afford more. Before leaving, he explains to her that many students have recently left school to find work in the cities, and he offers her a 10 yuan bonus if all the students are still there when he returns.
  Wei Minzhi, you look after the students. More than ten have already left. I don't want to lose any more. The mayor promised fifty yuan; he'll make sure you get it. If all the students are here when I get backânot one lessâyou'll get an extra ten yuan.
  
  
  âTeacher Gao, Not One Less (11:08â11:27)
  When Wei begins teaching, she has little rapport with the students: they shout and run around instead of copying their work, and the class troublemaker, Zhang Huike, insists that "she's not a teacher, she's Wei Chunzhi's big sister!" After putting the lesson on the board, Wei usually sits outside, guarding the door to make sure no students leave until they have finished their work. Early in the month, a sports recruiter comes to take one athletic girl, Ming Xinhong, to a special training school; unwilling to let any students leave, Wei hides Ming, and when the village mayor (Tian Zhenda) finds her, Wei chases after their car in a futile attempt to stop them.
  One day, after trying to make the troublemaker Zhang apologize for bothering another student, Wei discovers that Zhang has left to go find work in the nearby city of Zhangjiakou. The village mayor is unwilling to give her money for a bus ticket to the city, so she resolves to earn the money herself, and recruits the remaining students to help. One girl suggests that they can make money by moving bricks in a nearby brickyard, and Wei begins giving the students mathematical exercises centered on finding out how much money they need to earn for the bus tickets, how many bricks they need to move, and how much time it will take. Through these exercises and working to earn money, her rapport with the class improves. After earning the money, she reaches the bus station but learns that the price is higher than she thought, and she cannot afford a ticket. Wei ends up walking most of the way to Zhangjiakou.
  
  
  
  
  
  Zhangjiakou
  
  
  
  Beijing
  
  
  
  
  Location of Zhangjiakou, relative to Beijing
  In the city, Wei finds the people that Zhang was supposed to be working with, only to discover that they had lost him at the train station days before. She forces another girl her age, Sun Zhimei, to help her look for Zhang at the train station, but they do not find him. Wei has no success finding Zhang through the public address system and "missing person" posters, so she goes to the local television station to broadcast a missing person notice. The receptionist (Feng Yuying) will not let her in without valid identification, though, and says the only way she can enter is with permission from the station manager, whom she describes as "a man with glasses". For the rest of the day, Wei stands by the station's only gate, stopping every man with glasses, but she does not find the station manager, and spends the night asleep on the street. The next day the station manager (Wu Wanlu) sees her at the gate again, through his window, and lets her in, scolding the receptionist for making her wait outside.
  Although Wei has no money to run an ad on TV, the station manager is interested in her story and decides to feature Wei in a talk show special about rural education. On the talk show, Wei is nervous and hardly says a word when the host (Li Fanfan) addresses her, but Zhangâwho has been wandering the streets begging for foodâsees the show. After Wei and Zhang are reunited, the station manager arranges to have them driven back to Shuiquan village, along with a truckload of school supplies and donations that viewers had sent in. Upon their return, they are greeted by the whole village. In the final scene, Wei presents the students with several boxes of colored chalk that were donated, and allows each student to write one character on the board. The film ends with a series of title cards that recount the actions of the characters after the film ends, and describe the problem of poverty in rural education in China.
question: How old is the substitute teacher?
answer: 13