1, additive commutative law: a+b = b+a.

2. Additive associative law: (a+b)+c=a+(b+c).

3. Multiplicative commutative law: aXb=bXa.

4. Multiplicative association law: (aXb)Xc=aX(bXc).

5. Multiplication and distribution law: (a+b) Xc=aXc+bXc.

6、aXc+bXc =(a+b)Xc； aXc-bXc =(a-b)Xc； (a-b) Xc= aXc-bXc .

7. Continuous decline: A-B-C = A-(B+C); A-(B+C) = A-B-C.

8. Division: a ÷ b ÷ c = a ÷ (bxc); a \(bXc)= = a \b \c .

9. Increase and decrease: A-B+C = A+C-B.

10, multiplication and division: aXb÷c=a÷cXb.

1 1, division and distribution law: (a+b) ÷ c = a ÷ c+b ÷ c; (a - b)÷c=a÷c - b÷c .

The significance of doing simple operations:

The significance of simple operation is that it can improve the speed and accuracy of calculation and reduce the possibility of errors. Simple operation is a skill and method, which can transform the original complex calculation problem into a simpler and easier calculation form through proper processing and transformation.

Using simple operation skills can reduce the complicated calculation process, save time and energy, and easily solve complicated calculation problems. For example, in the process of oral calculation, if you can flexibly use mathematical knowledge such as multiplication and division, distribution method and associative law, you can quickly complete complex multiplication and division operations.

Matters needing attention in simple operation

1. Understand the calculation rules: Before using simple operation skills, make sure that you have a clear understanding of the corresponding calculation rules and mathematical principles. This can avoid mistakes and misuse of operation methods.

2, pay attention to the handling of symbols: in the process of operation, we should be careful to handle symbols, especially negative signs, parentheses, etc. Correct use of symbols can avoid calculation errors.

3. Conversion between decimals and fractions: When it comes to the operation of decimals and fractions, it is necessary to ensure the correct conversion between different forms. Pay attention to the relationship between decimals and fractions to avoid calculation errors.

4. Follow the calculation order: when performing simple operations, follow the correct calculation order, such as multiplication and division before addition and subtraction, and follow the operation rules. Pay attention to the priority of operations to ensure that the calculations are completed in the correct order.

5. Check the calculation results: After the operation is completed, carefully check the calculation results and compare them with the expected results. If possible, you can use a calculator or other tools to verify the accuracy of the calculation.

6. Practice and proficiency: Simple operation requires some practice and proficiency. Through repeated practice and application, the calculation speed and accuracy can be improved.