1. Counting is a mathematical behavior of repeatedly adding (or subtracting) 1. It is usually used to calculate how many objects there are or to place any number of objects (the first object is calculated from the beginning, and the remaining objects correspond to natural numbers starting from two). In addition, counting can also be used (mainly for children) to learn the knowledge of number and number system. The inclusion count is usually used to calculate the number of days in the calendar.

2. Early definition: the discipline of studying the shape and size of the earth and determining the coordinates of ground points. Current definition: the study of the shape, size, position, direction and distribution of various objects in three-dimensional space.

The content of surveying includes two parts: measurement and layout. Measurement refers to the use of measuring instruments and tools to obtain a series of measurement data through measurement and calculation, or to draw the terrain of the earth's surface into a topographic map. Plane layout refers to marking the positions of planned buildings and structures on the drawings on the ground as the basis for construction.

3. Measuring tools: length ruler and vernier caliper; Quality-balance; Timer; Volume-Measurement steps of liquid or irregular solid: measuring cylinder &; measuring glass

4. Sorting is a common operation in computers, and its purpose is to adjust a group of "unordered" record sequences into "ordered" record sequences.

Extended data:

Mathematics is an abstract concept for counting, marking or measuring, and it is a simple symbolic record form (or measurement) for things with the same nature or homogeneity. A series of symbols representing numbers, including numbers and operation symbols, are collectively called the numeration system. In daily life, numbers usually appear on signs (such as roads, telephone numbers and house numbers), serial indicators (serial numbers) and codes (ISBN).

In mathematics, the definition of number is extended to include abstract concepts such as fraction, negative number, irrational number, transcendental number and complex number. At first, people only thought that the number of a certain part was a number, but later, with the need, the concept of number gradually expanded; For example, Pythagoras believed that numbers must be represented by the ratio of integers to integers. Later, it was found that irrational numbers could not be expressed in this way, which caused the first mathematical crisis. However, people gradually accepted the existence of irrational numbers and expanded the concept of numbers.

The arithmetic operations of numbers (such as addition, subtraction, multiplication and division) are extended to abstract digital systems, such as groups, rings and fields, in the branches of abstract algebra.

Baidu Encyclopedia-Numbers (Mathematics)