Don't. According to the query of official website of Jiangnan University, there is no need for extra exams for the mathematics major in the cross-examination of Jiangnan University, and only need to take the postgraduate entrance examination for the mathematics major according to the normal postgraduate entrance examination process. Jiangnan University, located in Wuxi City, Jiangsu Province, is a university directly under the Ministry of Education of People's Republic of China (PRC), which was co-founded by the Ministry of Education and the People's Government of Jiangsu Province. It ranks among the national "double first-class", "21engineering" and "985 engineering advantage discipline innovation platform" and is selected as the national "165438".