1, Zhang Heng (78- 139), word. Han nationality, a native of Xi 'e, Nanyang (now Shiqiao, Nanyang City, Henan Province), is one of the five saints in Nanyang, and is also known as the four masters of Han Fu with Sima Xiangru, Yang Xiong and Ban Gu. China was a great astronomer, mathematician, inventor, geographer and writer in the Eastern Han Dynasty. He successively served as Langzhong, Taishiling, Shizhong and Hejian. In his later years, he became the minister of history of the DPRK due to illness. Yu Yonghe died in the fourth year (139) at the age of 62. In the Northern Song Dynasty, it was named Bo Er of Xi.

2. Zu Chongzhi (429-500) Wen Yuan was an outstanding mathematician and scientist in the Southern and Northern Dynasties. He has received scientific knowledge from home since he was a child. When I was young, I entered Hualin University and engaged in academic activities. Its main contributions are in mathematics, astronomical calendar and machinery. In mathematics, he wrote the seal script, which was included in the famous Ten Arithmetic Books, as an arithmetic textbook for imperial academy in the Tang Dynasty, but it was later lost. Zu Chongzhi calculated that the true value of pi t was between 3. 14 15926 and 3. 14 15927, which was equivalent to the seventh place after the decimal point, and it was the most advanced in the world at that time.

3. Guo Shoujing (123 1 year-1316 years) was born in Xingtai County, Shunde Province (now Xingtai County, Hebei Province). Yuan dynasty (1206- 1368)

North Korea's famous astronomer, mathematician and expert in water conservancy engineering. In his early years, he studied under Liu, Liu, Liu and Liu, and later entered the Taishiling. He is a college student in Zhaowen Museum. He knows about Taishi Museum and is called "Guo Taishi". Yuan Renzong extended his life for three years (13 16), and Guo Shoujing died at the age of 86. He is the author of fourteen kinds of astronomical calendar works, such as "Push Step" and "Licheng".