In mathematics, "plus sign" is a common symbol, which usually means the operation of modulo a number or a vector. On the two-dimensional plane, for the point (x, y), the result is $ \ \ sqrt {x 2+y 2} $. In the three-dimensional space, the topping operation becomes the module of the three-dimensional vector, that is, the topping operation is performed on the vector (x, y, z), and the result is $ \ \ sqrt {x 2+y 2+z 2} $. It can be seen that the above addition operation plays a very important role in mathematics.

Besides the application in mathematical theory, the above symbols are also widely used in physics and engineering. Especially in the fields of mechanics, electricity, etc., the above addition operation is used to solve important physical quantities such as force, electric field and its potential energy. For example, electrostatic field, if the charge distribution is known, the above calculation of adding points is needed to solve the problem of potential distribution. In thermodynamics and statistics, the above points can be used to express the average kinetic energy of molecules.

Besides addition symbols, there are many other mathematical symbols in mathematics, such as addition, subtraction, multiplication and division, equal sign, parentheses and so on. The application form and meaning of these symbols are precise and clear, and strict mathematical symbol specification can effectively reduce ambiguity and misunderstanding in mathematics. Therefore, it is very important for people who study mathematics to master mathematical symbols and symbol specifications skillfully, which not only helps to understand mathematical principles, but also improves their ability to apply mathematics and lays a solid foundation for future study and research.