The accuracy of elementary arithmetic of integers, fractions and decimals in class must be 100%, and there must be a certain speed, which is the foundation. Paying attention to the flexibility of calculation after class actually permeates the application of thinking methods, such as the law of simple calculation, the elimination of split terms, letter algebra, decomposition and consistency, the induction of general terms, the application of formulas and so on.

Although it is also a calculation, the difficulty level is really different from basic to advanced. You need to combine your own study preparation and improve step by step.

2. Application questions

In fact, I don't agree that you can learn math well in advance. Mathematics needs in-depth study. Compared with the knowledge level, that is the simplest. Spend more time on some comprehensive, complex and unfamiliar topics, think deeply, break through, find a breakthrough with divergent thinking in many directions, and draw conclusions with rigorous thinking and reasoning.

For example, application problems, basic application problems such as fractions and percentages, complex trip problems, solving complex problems with equations and so on. Solving problems and examining comprehensive mathematical thinking ability require the integration of multiple thinking.

Three characteristics of age problem

Age problem: an applied problem to find the multiple relationship between two people's ages years ago or years later is called age problem.

Three basic characteristics of the age problem:

The age difference between two people is constant.

② The age of two people increases or decreases at the same time.

(3) The multiples of two people's ages are changing.

Law of solving problems: Grasping the age difference is a constant, and the multiple is the key to change every year.

Example: Father is 54 years old and son 18 years old. A few years ago, my father was seven times as old as my son.

What is the age difference between father and son? 54 C 18 = 36 (years old).

A few years ago, my father was several times older than my son. 7 - 1 = 6。

How old was my son a few years ago? 36÷6 = 6 (years old).

A few years ago, the father was seven times as old as his son. 18 C 6 = 12 (year).

A: Before 12, the father was seven times older than his son.