Basic knowledge points of mathematics in the first volume of the fourth grade
1, meaning of natural number integer
1, 2, 3 ... used to represent the number of objects is called natural number. There is no object, which is represented by 0. 0 is also a natural number. They are all integers.
The smallest natural number is 0, there is no natural number. The number of natural numbers is infinite.
2. Counting units: one (one), ten, one hundred, one thousand, ten thousand, one hundred thousand, one million, ten million, one hundred million … are all counting units. Where "one" is the basic unit of counting.
3. Decimal counting method 10 1 Yes 10, 10 is 100 ... The propulsion rate between every two adjacent counting units is 10. This counting method is called decimal counting method.
4. Numbers
Counting units are arranged in a certain order, and their positions are called numbers.
5. How to read integers: from high to low, read step by step. When reading the 110 million level, first read according to the reading method of the 100 level, and then add a word "100 million" or "10 thousand" at the end. The zeros at the end of each stage are not read, and only a few zeros of other digits are read.
6. Writing of integers: from high to low, writing step by step. If there is no unit on any number, write 0 on that number.
7. How to write more than ten thousand:
(1) A number contains 10,000 levels and 100 million levels, so write it step by step.
(2) When writing numbers, write a few words where the numbers are higher, and write zero placeholders where there is no unit.
8. Compare the size of two numbers:
When the number of (1) digits is different, the number with more digits is large and the number with less digits is small;
(2) If the number of digits is the same, the larger the number of digits, the larger the number; If the first place is the same, look at the next place, and so on.
9, the whole ten thousand, hundreds of millions of rewriting:
(1) is rewritten as a number with "ten thousand" as the unit, four zeros after the ten thousand digits are removed, and a word "ten thousand" is added.
(2) Rewrite it into a number with "100 million" as the unit, remove eight zeros after the hundred million digits, and add a word "100 million".
10, divisor and exact number:
Some figures are preceded by the word "about", which is inaccurate. Numbers like this are called "divisors".
"Rounding method": When taking the divisor, which digit should be reserved as required, and the number after this digit is called "mantissa". If the number of digits of the mantissa is less than 5, the mantissa is removed. If the number of digits of the mantissa is greater than or equal to 5, the mantissa is truncated and "1" is added to its previous digit. This method is called rounding method.
"Omitting the mantissa after 10,000 bits or 100 million bits to find the divisor" means to accurately (reserve) a number to 10,000 bits or 100 million bits by rounding.
(1) Use "10,000" as the approximate figure, and then decide whether it is "four hospitals" or "five schools" depending on thousands of figures.
(2) The approximate figure of "100 million" depends on the figure of 10 million, and then decide whether it is "four" or "five".
(3) Whether using "10,000" or "100,000,000" as the unit, when writing the divisor, we should use the equal sign (substance) to connect them, and write "10,000" or "100,000" at the end.
1 1. Finding similarities between divisor and rewriting number: Finding divisor and rewriting number means expressing a larger number as an integer "10,000" or "100 million" followed by a word "10,000" or "100 million".
Difference: Finding divisor is to change a number into a divisor, and the size of the number has changed; The rewriting of numbers is just to write a large number into a number with "ten thousand" or "hundred million" as the unit, and the size has not changed.
12, digital coding. Numbers can be used not only to represent quantity and order, but also to encode. The numbers in the code represent specific meanings. The coding is orderly.
Knowledge points of mathematics practice in the first volume of the fourth grade
1. Fill in the blanks.
1.2 hectares = () square meters
2. 10 km2 = () hectares
3.50000 square meters = () hectares
4.400 hectares = () square kilometers
5. 1 km2 = () m2
6.3 million square meters = () square kilometers
2. Judge whether the following statement is correct.
1. The area of a square with a side length of 1 00m is1hectare ().
2. 1 km2 = 1 10,000 m2. ( )
The area of a classroom is 80 square centimeters. ( )
4.5 hectares = 50,000 square meters. ( )
The relatively large land area is generally measured in square kilometers. ( )
3. multiple choice questions.
1. The propulsion rate between square kilometers and hectares is ().
10 b . 100 c . 1000d . 10000
2. The area of West Lake in Hangzhou is about 600 ()
A. square meters, b square kilometers, c hectares and d square centimeters
A square wheat field is 400 meters long and can harvest 3 tons of wheat per hectare. This square wheat field can harvest () tons of wheat.
48-480 AD
4. 100 The square with a side length of 1000 meters has an area of () hectares.
10 b . 100 c . 1000d . 10000
A playground with a length of 200 meters and a width of 100 meters, if the length and width are doubled, the area will increase by () hectares.
A.2 B.4 C.6 D.8
4. Fill in the appropriate company name in ().
1. Mount Huashan in Xiyue, one of the five mountains in China, covers an area of about 148 ().
2. The school playground covers an area of about 10000 ()
Beijing Olympic Forest Park covers an area of about 680 ().
4. The Bird's Nest covers an area of about 20 ().
5. China's marine area is about 4.7 million ().
Verb (abbreviation of verb) is filled with ">" in (). , "< or" = ".
3 square kilometers () 30 hectares
1 100 m2 () 1 hectare
500 hectares (5 square kilometers)
700,000 square meters () 7 square kilometers
2 hectares () 200,000 square meters
4,000 hectares (4 square kilometers)
Mathematics learning skills in the fourth grade
First of all, create a good start and stimulate interest.
A good beginning is half the battle. Teachers should first bring smiles into the classroom, infect students with teachers' good taste, promote students to form a good psychological situation, and make necessary psychological preparations for a class. If the prologue is well spoken, it will make students eager to pursue new knowledge, stimulate their interest in learning and attract their attention, just like throwing a stone on a calm lake, which will arouse the ripples of thinking and produce the appeal that they are eager to listen to. Therefore, we should strive to launch a new curriculum of "novelty, interest, strangeness and novelty".
Second, create problem situations and implement heuristic teaching to stimulate students' cognitive interest.
The new curriculum advocates heuristic teaching. Heuristic teaching has great advantages over traditional cramming teaching. To implement heuristic teaching, the key is to create problem situations. Creating problem situations refers to learning situations that are difficult and require students to work hard and try their best. So how to create a problem situation better? This requires teachers to study textbooks carefully, dig deep into the internal laws of knowledge and the relationship between old and new knowledge, fully understand the existing cognitive structure of students, and stimulate students' interest and positive thinking activities through ingenious forms, thus creating a good problem situation. For example, in the first class, I used the method of telling stories to create problem situations. I first drew a beautiful forest on the blackboard, and then pasted a white rabbit, a red panda, a lion, a squirrel and a pony in turn. Storytelling: A group of cute little animals came to the beautiful forest. They all moved to their new homes today. Now, let's go and see where they all live ... In this class, the teacher created a vivid and interesting question situation. We make up stories and tell stories together, which makes students feel that they have entered a beautiful home. Stimulate students' interest and induce further positive thinking activities through more ingenious and novel forms.
Third, change the presentation of examples and exercises to stimulate students' interest in learning.
The new textbook provides rich teaching resources for teachers, and the presentation of mathematics content in the textbook is also close to the reality of children's life, which conforms to the age characteristics of first-year students. But these things are still static after all, and they still lack the attention and interest of students. Children in lower grades are often more interested in active things. If we can make these static resources active and further increase their interest, we will be able to firmly grasp the students' eyes. For example, in the teaching of "10 understanding", I designed ten numbers from 0 to 90 as anthropomorphic "digital children" and presented them on the blackboard one by one. Seeing that abstract numbers have grown into hands and feet and become elves who can cry and laugh, students' enthusiasm is extremely high.
Fourth, let students operate the experience and stimulate students' interest.
(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.
Summary of basic knowledge points of mathematics in grade four;
★ Basic knowledge points of mathematics in the first volume of the fourth grade
★ Summarize the knowledge points of the first volume of mathematics in the fourth grade of primary school.
★ Summary of Mathematics Knowledge Points in Grade Four
★ Basic knowledge points of mathematics in the fourth grade of primary school
★ Guidance of mathematics learning methods in the fourth grade of primary school
★ Summarize the knowledge points of fourth grade mathematics.
★ Summarize the knowledge points of fourth grade mathematics.
★ Summary of Mathematics Knowledge Points in Grade Four
★ Summary of Mathematics Knowledge Points in Grade Four
★ Summarize and sort out the knowledge points of fourth grade mathematics.