20 17. According to Daoke Baba's information, Weifang used the Qingdao version of primary school mathematics textbook on 20 17. Qingdao edition of primary school mathematics textbooks is divided into six-year edition and five-year edition, which are mainly used in Shandong Province. Qingdao, Zaozhuang, Tai 'an, Jining, Weifang and Liaocheng use six-year textbooks.