You asked the right person this question. I study chemistry. Chemistry remembers many things. If you can't remember them, you can't work out the problem. The difficulty is not very deep, or the amount of questions is particularly large.

You only have time to write all the time, but you have no time to think, so you should not only memorize it, but also use it well. I took math (agriculture) in my dormitory, and he got more than 130. According to him, the topic is quite simple. As long as you can do one type of problem, other problems of the same type will be solved, and you will certainly do it, but you can also do it in other ways. There are many solutions to a problem, but this one is not easy to remember, mainly through mastery.

I have introduced the characteristics of these two courses to you, so you can choose the specific ones!

Count, Shu, count from the building.

(1) pictophonetic characters. From (pū), the sound of the building. Original meaning: points; Do the math.

② The original meaning is the same [counting]

It is an abstract concept for counting, marking or measuring, and it is a simple symbolic record form (or measurement) of things with the same nature or homogeneity. A series of symbols representing numbers, including numbers and operation symbols, are collectively called the numeration system.

In daily life, numbers usually appear on signs (such as roads, telephone numbers and house numbers), serial indicators (serial numbers) and codes (ISBN). In mathematics, the definition of number is extended to include abstract concepts such as fraction, negative number, irrational number, transcendental number and complex number.

At first, people only thought that the number of a certain part was a number, but later, with the need, the concept of number gradually expanded; For example, Pythagoras believed that numbers must be represented by the ratio of integers to integers. Later, it was found that irrational numbers could not be expressed in this way, which caused the first mathematical crisis. However, people gradually accepted the existence of irrational numbers and expanded the concept of numbers.

The arithmetic operations of numbers (such as addition, subtraction, multiplication and division) are extended to abstract digital systems, such as groups, rings and fields, in the branches of abstract algebra.