1, any number multiplied by 1 equals the number itself.

2. Any number multiplied by 2 can get an even number, the last bit of the product appears twice, and 2, 4, 6, 8 and 0 appear once.

Every number of 3,3 and 1 to 9 is multiplied, the last digit of the product is 1 to 9, and the sum of the ten digits and the single digits of the product is a multiple of 3.

4. Any number multiplied by 4 can get an even number, the last bit of the product appears twice, and 2, 4, 6, 8 and 0 appears once.

5. The last bit of the product of any number and 5 can only be 0 or 5.

The basic concept of multiplication:

Multiplication is a basic mathematical operation, which is used to represent and calculate the accumulation or combination of multiple identical quantities. In multiplication, two or more numbers are called factors, and the result of their multiplication is called product. Multiplication usually uses the symbol ×, for example, ab means that two numbers A and B are multiplied. ..

The basic concepts of multiplication include:

1, commutativity of multiplication: multiplication is commutative, that is, a× b = b× a. This means that the order of multiplication does not affect the final product.

2. Distribution of multiplication: Multiplication satisfies the distribution law, that is, for any three numbers A, B and C, there is a×(b+c)=(a×b)+(a×c). This means that multiplication has a distributive effect on addition.

3. Unit of multiplication: 1 is the unit of multiplication, and any number multiplied by 1 equals itself, that is, a×1= a.

Application fields of multiplication:

Multiplication is widely used in various fields, including but not limited to:

1, arithmetic mathematics: multiplication is one of the basic arithmetic operations, which is used to calculate the product of numbers. It is also used to solve various mathematical problems, such as algebra, geometry and probability.

2. Science and engineering: multiplication is often used to express and calculate various physical quantities and numerical relationships in scientific research and engineering fields. For example, the multiplication in Newton's second law, F=ma, represents the relationship between force and acceleration.

3. Economic finance: Multiplication is used to calculate key concepts such as compound interest, growth rate and return on investment in economic and financial analysis. It is also used to calculate currency exchange rate and inflation rate.

4. Computer science and programming: Method is one of the basic operations in computer programs, which is used to perform various numerical calculations and algorithmic operations. The processor and hardware in the computer also use multiplication circuits for numerical calculation.

5. Statistics: In statistics, probability and joint probability distribution are calculated by multiplication to solve problems related to probability and random variables.

6. Practical problems in life: multiplication is widely used to solve various practical problems in daily life, such as shopping calculation, recipe adjustment, travel planning, time management, etc.