九章算术
It was specified in Tang dynasty laws on examination that "Sunzi Suanjing" and the "Computational Canon of the Five Administrative Sections" together required one year of study; "The Nine Chapters on the Mathematical Art" plus "Haidao Suanjing" three years; "Jigu Suanjing" three years; "Zhui Shu" four years; and "Zhang Qiujian" and "Xia Houyang" one year each.