Basic knowledge points of mathematics in the first volume of the fourth grade
1, line
(1) straight line
A straight line has no end; Infinitely long; You can draw countless lines after one o'clock, and only one straight line after two o'clock.
(2) Ray
Ray has only one endpoint; Infinitely long.
⑶ line segment
A line segment has two endpoints, which are part of a straight line; Limited length; In the connection between two points, the segment is the shortest.
The length of the line segment between two points is the distance between two points.
Connection of straight ray line segments: all are straight lines, and both rays and line segments are part of a straight line.
(4) The positional relationship between two straight lines in the same plane is parallel and intersecting.
5] parallel lines
Two straight lines defined on the same plane and not intersecting are called parallel lines. The straight line A is parallel to B, and the straight line B is also parallel to A. ..
At a point outside the straight line, you can only draw a straight line parallel to the known straight line.
There are countless vertical segments between two parallel lines, all of which are equal in length. The vertical segments between parallel lines are equal everywhere.
The painting method is one in two, three moves and four paintings.
[6] vertical line
When two straight lines intersect at right angles, they are said to be perpendicular to each other, one of them is said to be perpendicular to the other, and the intersection point is called vertical foot.
nature
After a point (on or off the line), you can only draw a straight line perpendicular to the known straight line.
The vertical line segment drawn from a point outside the straight line is the shortest, and its length is called the distance from that point to the straight line.
The painting method is one in two, three in three and four in four.
Summary of Mathematics Knowledge Points in Grade Four
Algorithms and simple operations
First, the law of addition:
1, additive commutative law: Two numbers are added, the addend positions are exchanged, and the sum is unchanged. a+b=b+a
2, the law of addition and association: three numbers are added, you can add the first two numbers first, and then add the third number; Or add the last two numbers first, and then add the first number, and the sum remains the same. (a+b)+c=a+(b+c)
These two laws of addition are often used together.
For example:165+93+35 = 93+(165+35) What is the basis?
3. The essence of continuous subtraction: one number subtracts two numbers continuously, which is equal to the sum of this number MINUS those two numbers. a-b-c=a-(b+c)
Second, the law of multiplication:
1, multiplication method of substitution: When two numbers are multiplied, the exchange factor position remains unchanged. a×b=b×a
2. Multiplication and association law: When three numbers are multiplied, you can multiply the first two numbers and then the third number, or you can multiply the last two numbers and then the first number, and the product remains unchanged. (a×b)×c=a×(b×c)
These two multiplication laws are often used in combination. Such as: 125×78×8.
3. Multiplication and distribution law: the sum of two numbers is multiplied by one number. You can multiply these two numbers by this number first, and then add up the products.
(a+b)×c=a×c+b×c (a-b)×c=a×c-b×c
Mathematics learning methods and skills
Let students operate the experience and stimulate their interest in participation.
(A) let students "enter" the exercises in the textbook. When I let students practice, I like to let them imagine the characters in the book as themselves. Because of this, students will feel as if this topic is closer to them and feel more intimate.
(B) to create practical opportunities for students to participate, so that they can experience success in participation. For example, in the teaching of "increasing with decreasing", I made some swan headdresses in advance, so that nine children in my class could wear them and perform the scene of swans flying around. As soon as the following children saw the "role model" of this activity, they were deeply attracted and their enthusiasm was fully mobilized. Teachers can easily highlight key points and break through difficult points.
(3) Make use of students' aggressive psychological characteristics, organize some activities such as math games and answering questions in competitions, so that every student has the opportunity to participate. Learning competition is induced by ranking or winning prizes in the competition, which can stimulate students' need for self-improvement, thus improving students' learning enthusiasm and affecting learning effect to a certain extent. Generally speaking, learning competitions affect middle-level students, so most children will make continuous progress through hard work in the competition. If competition and self-competition are combined, advanced students will be more advanced, and backward students will also become advanced. This also helps to prevent students' pride and inferiority. For example, in the revision class of addition, subtraction, multiplication and division, addition, subtraction, multiplication and division and mixed addition and subtraction within 10, I adopted the way of group competition, so that every student had the opportunity to participate. The competition is divided into three parts: oral calculation, I am a small examiner, eager to answer thinking questions. Each item is participated by the whole class, and different people are selected from each group to judge and recorded in the scores of that group. Because the students have a strong sense of collective honor, reviewing their lessons in the form of competitions has greatly improved their enthusiasm for learning, and the classroom arrangement is also hierarchical. Students' mathematical thinking ability and understanding ability have been further improved, and their language expression ability has also been greatly improved.
Incentive measures should be appropriate and diversified.
The new curriculum advocates that the evaluation of students should not only look at the results, but should pay attention to the process and ignore the results. My incentive measures for students in teaching are as follows:
(A) good at discovering the advantages of students, often praise. No matter who has an advantage in learning, even if it is only a little, I will not hesitate to praise it. For example, if a student's calligraphy has improved, his oral calculation speed is fast, his hands are raised frequently, or his problem-solving methods are novel, I will praise them in time, so that students will have greater confidence to meet the challenges behind.
(two) the combination of verbal rewards and material rewards. Junior students tend to be given material rewards because they are still young. I often draw some small pictures and make some headdresses and chest ornaments to show my affirmation of their study.
(3) Linking individual honor with collectivity to cultivate students' team spirit. Each group has a simulated "ladder" with a small red flag at the top. If the members of any group have made progress, there will be one more footprint on the ladder of this group. Whoever climbs the ladder first wins. Students like this kind of reward measure very much, and everyone hopes that their group can climb around quickly and win a small red flag.
Fourth grade mathematics unit knowledge point induction related articles;
★ Summarize the knowledge points of the first volume of mathematics in the fourth grade of primary school.
★ Knowledge points in the first volume of fourth grade mathematics
★ Summary of knowledge points in the first volume of fourth grade mathematics
★ Summarize the knowledge points of the fourth grade math unit.
★ Summary of Mathematics Knowledge Points in Grade Four
★ Summary of knowledge points in the first volume of fourth grade mathematics
★ The induction of mathematics knowledge points in the first volume of the fourth grade of primary school
★ Knowledge points of the first unit of mathematics in the first volume of grade four
★ Summarize the knowledge points of fourth grade mathematics.
★ Summarize and sort out the knowledge points of fourth grade mathematics.