The reverse is the inverse operation of the law of multiplication and distribution.
The main formula of the multiplicative associative law is (a×b)×c=a×(b×c), and the operation order can be changed in the multiplication operation. The law of multiplication and association is that three numbers are multiplied, the first two numbers are multiplied, or the last two numbers are multiplied first, and the product is unchanged. It can also be written as (ab)c=a(bc)
At present, the "multiplication and division method" and its inverse operation in primary school textbooks are collectively called "multiplication and division method"
Multiplication and distribution law: a×b+a×c=a×(b+c) or a× (b+c) = a× b+a× c.
Law of multiplicative association: (a×b)×c=a×(b×c)
Multiplicative commutative law: a×b=b×a
Understand? If you still don't know, keep asking.