What level did Kangxi reach in mathematics?

Kangxi's mathematics should be the best of all emperors. The analysis is as follows:

Nowadays, the professional terms of mathematics, such as "Yuan", "Secondary" and "Root (Solution)", were originally decided by Kangxi in China.

One of the teachers of Emperor Kangxi 14 years old was the Belgian missionary Ferdinand ferdinand verbiest, who taught the emperor astronomy and calendar calculation. Emperor Kangxi also studied the first chapter of Euclid's Elements translated by Matteo Ricci and Xu Guangqi, and ordered it to be translated into Manchu and Chinese. The emperor played a good abacus, and the speed was faster than that of Xifa.

Kangxi's ability to solve complex application problems really represented the top level of Chinese people at that time. He also has mathematical papers, such as the theory of imperial triangle reasoning algorithm and Pythagorean method.

In his later years, Kangxi established the first mathematics museum in China. "Chen Jian's officials who are good at mathematics have their own duties. He ordered Prince Dong Zhi to choose the children of the Eight Banners to learn algorithms." His pen pal Leibniz, a famous German mathematician, suggested that the emperor set up an academy of sciences. The Academy of Sciences has been built, but it is full of painters, sculptors, blacksmiths, coppersmith, and craftsmen who make astronomical instruments. Their task is to make strange objects with mathematical knowledge, not to lift an empire with their own technology.

Kangxi organized manpower to compile Essentials of Mathematics, which introduced the contents of arithmetic, geometry and trigonometry in the Middle Ages in the West and the new concept of logarithm, but Essentials of Mathematics did not involve analytic geometry and calculus. The essence of mathematics has the reputation of "encyclopedia of elementary mathematics"

To sum up:

Emperor Kangxi reached an incredible level in astronomy and mathematics, and he was able to make accurate long-distance measurements with instruments. Kangxi could even personally explain the geometric principles to his sons, and his attitude towards science was unique among the ancient emperors in China.