1, prime number: prime number, also known as prime number, refers to an integer greater than 1, and no other positive integer can divide its number exactly except 1 and itself. In other words, a prime number has only two positive factors, namely 1 and itself. For example, 2, 3, 5, 7, 1 1 are all prime numbers, because they can only be divisible by 1 and themselves.
2. Composite number: A composite number refers to an integer greater than 1, and besides 1 and itself, there are other positive integers divisible by it. In other words, a composite number has at least three positive integer factors, including 1, itself and other positive integer factors. For example, 4, 6, 8 and 9 are all composite numbers, because they can be divisible by other positive integers except 1 and itself.
3. Difference between prime numbers and composite numbers: a prime number is an integer with only two positive integer factors (1 and itself), and a composite number is an integer with at least three positive integer factors (including 1, itself and other positive integer factors). Prime numbers and composite numbers are the basic classifications of integers, which have important applications in number theory and other branches of mathematics.
Important concepts in mathematics
1, number and number: Mathematics is based on the concepts of number and number. Numbers include natural numbers, integers, rational numbers and real numbers, and their properties and relationships are studied mathematically. Algebra: the branch of science that studies the relationships and operations between mathematical objects. Include algebraic equations, polynomials, groups, rings and fields.
2. Vector and vector space: Vector and vector space are used to describe the size and direction of physical quantities and are important tools in physics and engineering. Probability theory and statistics: the field of studying randomness and data analysis. Probability theory involves the probability of random events, and statistics involves the method of extracting information from data.
3. Function: one of the core concepts in mathematics, which describes the relationship between input and output. Functions can be linear, polynomial, exponential, logarithmic, etc.