lǎo shī / zài / shù xué / kè / shàng / jiè shào / le / jiǔ zhāng suàn shù / de / lì shǐ / dì wèi

老师在数学课上介绍了《九章算术》的历史地位。

The teacher introduced the historical status of 'The Nine Chapters on the Mathematical Art' in math class.