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.
2. Angle
The definition of (1) angle leads to two rays from a point, and the graph is called an angle. This point is called the vertex of the angle, and these two rays are called the edges of the angle.
(2) Angle measurement Angle measurement unit is "degree", with the symbol "". Divide the semicircle into 180 equal parts, and the angle of each part is 1 degree. Write "1".
(3) Comparison of the size of the angle The size of the angle has nothing to do with the length drawn on both sides of the angle. The size of the angle depends on the size of both sides. The bigger the fork, the bigger the angle.
(4) The drawing method of angle is to draw a line, measure the angle, connect three lines and mark four. The angle a pair of triangles can draw is a multiple of 15.
(5) Classification of angles
① Acute angle: An angle less than 90 is called an acute angle.
② Right angle: An angle equal to 90 is called a right angle.
(3) Oblique angle: An angle greater than 90 and less than180 is called obtuse angle.
4 flat angle: the two sides of the angle form a straight line, and the angle formed is called flat angle. Boxer 180.
⑤ Fillet: One side of the corner rotates once and coincides with the other side. Fillet 360.
Knowledge points of fourth grade mathematics
1. Understanding of large numbers
Understanding of numbers within 1 100 million;
One hundred thousand:100000;
One million:100000;
Ten million:100000;
1 100 million:1010 million;
2. Several levels
Numeric grading is a way of reading Arabic numerals for people to remember. On the basis of numerical system (numerical order), read and write numbers according to the principle of three-digit or four-digit grading. Usually, in the writing of Arabic numerals, decimal points or spaces are used as the marks of each number level, and the numbers are separated from right to left.
3. Several levels of classification
(1) four-digit classification method
That is, a four-digit grading method. The habit of reading in our country is like this.
Such as: ten thousand (four zeros after counting), one hundred million (eight zeros after counting), and one trillion (12 zeros after counting, which is a normal number). ...
These levels are called Level 1, Level 10,000 and Level 100 million respectively. ...
(2) Three-digit classification
That is, the three-digit grading method. This western classification, this classification is also an internationally accepted classification. For example, thousands, followed by three zeros and millions, six zeros and one billion, and nine zeros.
4. Numbers
Numbers mean that when writing numbers, the numbers are arranged side by side in a line, and each number occupies a position. These positions are called numbers. Starting from the right end, the first place is the unit, the second place is the tenth place, the third place is the hundred places, the fourth place is the thousand places, and the fifth place is the ten thousand places, and so on. This shows that the concept of counting unit and number is different.
5. Generation of numbers
The origin of Arabic numerals: After the ancient Indians created Arabic numerals, they spread to the Arab region around the 7th century. By the 3rd century A.D./KLOC-0, the Italian mathematician Fibonacci wrote Abacus, in which he introduced Arabic numerals in detail. Later, these figures spread from the Arab region to Europe. Europeans only know that these numbers are imported from the Arab region, so they are called Arabic numbers. Later, these figures spread from Europe to all countries in the world.
Arabic numerals were introduced into China around 13 ~ 14 century. Because there was a number called "chip" in ancient China, which was easy to write, Arabic numerals were not popularized and used in China at that time. At the beginning of this century, with the absorption and introduction of foreign mathematical achievements by China, Arabic numerals began to be used slowly in China, and only now have they been popularized and used in China for more than 100 years. Arabic numerals have now become the most commonly used numbers in people's study, life and communication.
Math learning methods in the fourth grade
First, let the activities lead students into the mathematics hall.
Interest is the teacher, and interest is the motivation. Once students' interest in knowledge is aroused, they will actively participate, explore hard and listen attentively. Learning habits are the premise for students to actively participate in the learning process and improve the efficiency of classroom learning, and interest is also the basis for listening attentively. Therefore, in view of the characteristics of junior students, such as liveliness, poor control ability and inattention, teachers should try their best to make boring and simple knowledge teaching lively and interesting, and fully stimulate students' interest in learning. In order to attract students' attention and make them concentrate on listening in class, teachers must be full of energy in class and make efforts to make the language lively, interesting and clear, so as to make the class fascinating and make every student willing to listen. Let students insist on listening attentively, and on the basis of listening attentively, let students master classroom knowledge faster and more firmly, and improve their language expression ability.
Dewey, an American educator, believes that education is life. Add specific activities to teaching activities, let students participate in them, and let students have more opportunities to practice mathematics knowledge. For example, when learning the addition and subtraction of scores, design a supermarket shopping activity, set the prices of different commodities as decimals, let some students buy commodities as customers, and other students as salespeople to calculate the total price of commodities purchased by "customers". Under the guidance of the teacher, the students learned the addition and subtraction of decimals and their applications while experiencing supermarket shopping. Participatory activities in the teaching process give students the opportunity to participate independently, and they experience the happiness of mathematics application and mathematics learning. Designing wonderful activities will greatly increase students' interest in learning and have a strong sense of participation, which will greatly promote mathematics teaching.
Second, cultivate students' interest in discovering and applying mathematics from life.
Mathematics comes from life. Teachers should proceed from the reality of life and start with the tangible things around them at ordinary times to cultivate students' interest in learning, learning, discovering and practicing mathematics. For example, when I teach the content of "mirror symmetry" of observing objects, let students look in the mirror first, and then communicate in groups: the characteristics of people in the mirror, whether the front, back, up and down, left and right positions of people inside and outside the mirror have changed, and students can summarize through activities and communication: when looking in the mirror, people inside and outside will not change up and down, but the left and right positions will change.
1, in order to make the class more vivid, we should try our best to use vivid words with strong emotion, cadence and mild and changeable tone in teaching. For the evaluation of students, we should also pay attention to wording and tone, and give intensive encouragement and praise. In mathematics teaching, we try our best to make ourselves vivid and diverse, combining dynamic and static, so as to stimulate students' enthusiasm for learning and make them willing to actively express their views and ideas anytime and anywhere, from wanting to say to wanting to do. Because both oral and hands-on are ways to encourage students to think.
2. Experience the function of silent language in mathematics textbooks. Examples are arranged in each section of the mathematics textbook, and these examples are carefully designed to meet the actual situation of students at all levels, and most of them are illustrated. I pay attention to guiding students to realize the practicality, feasibility and importance of learning mathematics through examples in teaching. As a teacher, in addition to turning silent words into spoken language, we should also educate and encourage students, integrate their emotions and interests, and introduce students from the classroom into real life to achieve the purpose of teaching and educating people.
3. Use modern means to increase students' mathematical knowledge of various sensory stimuli at multiple levels. Multimedia software or courseware allows us to decompose mathematical knowledge into visual elements and transmit them to students' minds through sensory stimuli such as vision and hearing. So as to mobilize students' active cells in learning mathematics.
Third, infiltrate art education to stimulate interest in learning.
1, enrich the appearance through words and hands.
When I teach "square area", let students find the square around them first, then compare the areas, and then draw a square by themselves, thinking about why their areas are different and how to find the square area. After summing up the solution of square area, let the students compete to see who can calculate quickly. Finally, an example is given to illustrate how to calculate the area of a square object in daily life.
2. Arouse students' enthusiasm, express their opinions and pay attention to application.
In addition to cultivating students' thinking ability, mathematics discipline must not ignore students' oral expression ability. After learning mathematics, most students have various ideas about knowledge and application. We can't think that the training of oral expression ability is the patent of Chinese class. At this time, let students express their ideas and opinions more, which is helpful to improve students' interest in learning mathematics. At the same time, it also cultivates students' enthusiasm for pursuing true knowledge; It also eliminates students' learning tension and allows students to firmly master knowledge in a relaxed and happy environment.
3. Draw inferences from others and cultivate creativity.
Let students experience and participate directly, generate ideas in the activities, give students hands-on operation, and stimulate their interest in learning with the opportunity of thinking. In addition to stimulating students' thirst for knowledge in various ways, we should also pay attention to cultivating students' creative ability, that is, the ability to draw inferences from others, so as to expand students' thinking and increase their knowledge. For example, when teaching "parallelogram area", let students master the solution of parallelogram area by splicing two identical parallelograms into rectangles. At the same time, give students two identical trapezoids and remind them of similar methods to find the area, so that students can draw inferences and experience different graphics and the same method to find the area. At the same time, some performances can be designed appropriately, for example, let two students play with two trapeziums or parallelograms with the same shape, and try to form a rectangle after the performances meet. Small activities can stimulate students' creativity. During the whole performance, students' mood will be high and their enthusiasm for learning will be improved.
Fourth grade mathematics Qingdao edition knowledge point related articles;
★ Qingdao Edition Grade Four Volume I Math Unit 1 Exercise and Answers
★ Qingdao Edition Grade Four Mathematics Volume I Unit 2 Exercise Questions and Answers
★ Qingdao Edition Grade Four Volume One Math Final Examination Paper and Answers
★ Q&A of the Third Monthly Exam of Mathematics in Grade Four of Qingdao Edition (2)
★ Qingdao Edition Primary School Grade Four Volume 1 Mathematics Teaching Plan
★ Qingdao Edition Grade Four Mathematics Volume I Unit 1 Examination Paper and Answers
★ Qingdao Edition Grade Four Volume II Mathematics Final Examination Paper
★ Qingdao Edition Fourth Grade Mathematics Volume I Final Examination Questions
★ Qingdao Edition Grade Four Volume II Math Exercise
★ The first volume of the fourth grade math unit arranges mind maps.