Additive commutative law: A+B+C=A+C+B=B+C+A, you can change the position at will. This is additive commutative law.

For example, to calculate 45+93+55, you can add 45 and 55 first, which is equal to 100, and then add 93, and the answer is equal to 193, which is easier than directly calculating 45+93 and then adding 55.

Law of multiplicative association: (A*B)*C=(A*C)*B

For example, when calculating the value of (25*76)*4, multiply 25 by 4 and then multiply 76, that is, (25*4)*76=7600.