First, the definition and characteristics of positive numbers

1. A positive number refers to a real number greater than zero. On the number axis, a positive number is located on the right side of the origin, indicating the positive size and direction.

2. Features: Positive numbers are special cases of real numbers, isomorphic with negative numbers and zero * * * to form a group of real numbers. Positive numbers can represent the values of various specific actual quantities such as the number, distance, temperature and time of objects. Positive numbers have a series of special properties in mathematical operations, such as addition and multiplication of positive numbers, and they are still positive numbers.

Second, the symbolic representation of positive numbers.

1. sign convention: positive numbers are usually expressed without any sign, such as 1, 2, 3, etc. In mathematical expressions, positive numbers can be written directly or expressed by letters.

2. Positive sign (+): In order to clearly represent positive numbers, sometimes a positive sign (+) is added before the positive numbers, such as+1, +2, +3, etc. Positive sign is not very common in practical application, but is more used to emphasize the difference between positive and negative numbers.

Third, the operational nature of positive numbers.

1. Addition of positive numbers: When two or more positive numbers are added, the result is still positive. For example, 2+3=5.

2. Multiplication of positive numbers: when two or more positive numbers are multiplied, the result is still positive. For example, 2×3=6.

3. Division of positive numbers: When one positive number is divided by another positive number, the result is still positive. For example, 6÷2=3.

Fourth, the application fields of positive numbers

1. Mathematics: Positive number is one of the basic concepts in mathematical research and plays an important role in algebra, geometry, probability and other mathematical branches.

2. Physics: Positive numbers can be used to represent physical quantities such as mass, temperature, speed and force of an object.

3. Economics: Positive numbers can be used to represent economic indicators such as money quantity, commodity prices, income and profits.

4. Metrology: Positive numbers can be used to measure physical quantities such as length, time, weight and capacity.

5. Engineering: Positive numbers can be used to represent information such as size, pressure, current and voltage in engineering design.