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

Multiplicative commutative law: ab=ba

Law of multiplicative association: (ab)c=a(bc)

Multiplication and distribution law: a(b+c)=ab+ac.

Algorithm * * *: additive commutative law, additive associative law, multiplicative commutative law, multiplicative associative law and multiplicative distributive law, which should be mastered and applied flexibly on the basis of understanding.

The nature of operation refers to: one number plus the difference between two numbers; One number MINUS the sum of two numbers; One number MINUS the difference between two numbers; The quotient of one number multiplied by two numbers; A number divided by the product of two numbers; The quotient of one number divided by two numbers; The sum of several numbers divided by a number, etc. This part is only used for simple operation.

Algorithms include: four integer algorithms, four decimal algorithms and four fractional algorithms. It is required to master the algorithm on the basis of understanding and be skilled in using it to calculate.