1, additive commutative law: In an addition formula, two sums are added to the exchange position, and the sum is unchanged. This is the exchange law of addition. Alphabetic formula: a+b = b+a.
2. Addition associative law: In an addition formula, the first two numbers are added or the last two numbers are added unchanged, which is the associative law of addition.
3. Subtraction property: one number subtracts two numbers continuously, and this number can be used to subtract the sum of the other two numbers. The letter means: a-b-c=a-(b+c).
4. Multiplication commutative law: In a multiplication formula, the exchange positions of two factors are multiplied and the product is constant, which is the commutative law of multiplication. The letter means: a * b = b * C.
5. Multiplication and association law: In a multiplication formula, the first two numbers are multiplied or the product of the last two numbers is unchanged, which is the multiplication and association law. The letter means: a*b*c=a*(b*c).
6. Distribution law of multiplication: In a multiplication formula, a number multiplied by the sum of two numbers can be multiplied and added respectively, which is the distribution law of multiplication. The letter means: a * (b+c) = a * b+a * C.
7. Inverse operation of the law of multiplication and distribution: the product of one number multiplied by another number plus the product of itself multiplied by another number can add the other two numbers and multiply them by this number. The letter indicates: a*b+a*c=a*(b+c).
8. Quotient invariance: Divider and divisor are multiplied or divided by the same number (except 0) at the same time, and the quotient remains unchanged. The numerator and denominator of a fraction are multiplied or divided by the same number (except 0) at the same time, and the size of the fraction remains the same. The letter means: a ÷ b = (AC) ÷ (BC) = (a ÷ c) ÷ (b ÷ c) (c ≠ 0b ≠ 0).