Yang Sulian, a 72-year-old former Chinese teacher in Chengdu, Sichuan province, has chosen an unusual retirement project: teaching herself middle school mathematics. All her efforts are for the sake of her adopted granddaughter, Qianqian.

Yang still vividly remembers the day she found Qianqian, still a baby swaddled in a blanket. It was July 2003, and Yang was catching up with an old acquaintance. An elderly woman asked her to take care of the baby girl in her arms while she went to use the nearby public restroom, but the woman never returned.

Two notes from two different people were later found tucked in the baby's blanket. It turned out that the baby was first abandoned by her mother, a young, fresh college graduate who was not ready for her motherhood. Then the baby was given up a second time by the older woman. 

The reason the baby was abandoned a second time is that she was in poor health. Yang and her husband, though not well off, nevertheless chose to seek treatment for the baby girl, racking up medical bills of 11,000 RMB. At the same time, they made a plea through local media for help finding the baby's family. When the plea failed to yield any leads, Yang finally decided to adopt the girl and name her Qianqian.

Last year, Qianqian was admitted to a good school in Chengdu. Yang paid for Qianqian to attend a cram school in preparation for the entrance exam, and also tutored Qianqian herself, after first teaching herself the material. 

It wasn't an easy job, and Yang usually spends two to three hours studying every day. Regardless, Yang said that her biggest dream is to accompany her granddaughter until she finishes senior middle school.