Euler's achievements are mainly in the field of mathematics. 18th century, people call it Euler century. He has a thorough study of mathematical analysis and calculus, and famous works such as partial differential equations and elliptic function theory are one of the most important contents in the field of mathematics. Many of his research results are the basis of number theory. He also summed up the predecessors' research on algebra and finished the book Introduction to Algebra, which provides a good reference for beginners of algebra. Euler's achievements cover almost all aspects of mathematics, such as infinite series, elementary functions, simple complex functions, calculus, differential equations and so on. In addition to his attainments in mathematics, Euler has made remarkable achievements in mechanics, geometry and economics. He even combined music with mathematics to explain the uniqueness of music with mathematics.
Euler's achievement is not only academic but also an excellent teacher. He trained another great mathematician, Lagrange. It is said that in order to recommend this talented student, Euler hid his research results and published Lagrange's paper. Under the unreserved cultivation of Euler, Lagrange became a master of mathematics.
In his later years, Euler was blind, but this still did not stop his enthusiasm for mathematics. He persisted in his research with unimaginable perseverance and asked his assistant to help him write the article. Many of Euler's achievements were made after his blindness, which is really admirable.