1. additive commutative law: A+B = B+A.

The two addends exchange positions, and the sum remains the same. This is called additive commutative law.

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

Add the first two numbers or add the last two numbers first, and the total remains the same. This is the so-called law of additive association.

3. Multiplicative commutative law: a× b = b× a.

Exchanging the positions of two factors and keeping the product unchanged is called multiplicative commutative law.

4. Multiplicative associative law: (a×b)×c=a×(b×c) or a×b×c=a×(b×c).

Multiply the first two numbers or multiply the last two numbers first, and the product remains the same. This is the so-called multiplicative associative law.

5. Multiplication distribution law: (a+b)×c=a×c+b×c or (a-b) × c = a× c-b× c.

Inverse application of the law of multiplication and distribution: a×c+a×b=(a+b)×c or a× c-b× c = (a-b )× c.

When the sum of two numbers is multiplied by a number, you can multiply this number separately and then add it. This is the so-called law of multiplication and division.

6. In the mixed operation of addition and subtraction, the positions of subtraction and addend can be interchanged. However, when exchanging positions, you must "move" with the previous operation symbols, and the operation result will not change.

Namely: a-(b-c) = a-b+c; a-(b+c)=a-b-c

7. In the mixed operation of multiplication and division, the order of multiplication and division can be interchanged, and the result of the operation will not change. But when you change places, you must "move" with the previous operation symbols.

Namely: a ÷ b ÷ c = a ÷ (b× c) = a ÷ c ÷ b; a \b×c = a \b \c