Key points of fourth-grade students' learning mathematics
First, the issue of normalization.
1. It costs 0.6 yuan money to buy five pencils. How much is it to buy the same pencil 16?
2. Three tractors cultivate 90 hectares in three days. According to this calculation, five tractors are 6? How many hectares of arable land are there?
Second, summarize the problem.
1. The garment factory originally made a set of 3.2-meter clothes cloth. After improving the cutting method, each set of clothes cloth was 2.8 meters. How many sets of cloth can you make now?
2. Xiaohua reads 24 pages of books every day, and finishes the book Red Rock in 12 days. Xiaoming reads 36 pages a day. How many days can he finish Hongyan?
Thirdly, the problem of connecting passengers.
1, Xiaodong practices 2 calligraphy words every day, each 16 words. How many words does Xiaodong write in a week (7 days)?
2, a square, ***8 columns, Xiao Ming is in the third column, there are five people in front of Xiao Ming and six people behind him. How many people are there in this square?
A team has 8 columns, and Xiaoming is in the sixth column. From the back, Xiao Ming is the fifth person, and from the back, Xiao Ming is the sixth person. How many people are there in this team?
4. A school donated money to Sichuan disaster area. There are 6 grades in the school, 3 classes in each grade, and the average donation per class 123 yuan. How much did they donate?
Each bookshelf has three layers, and each layer can hold 36 books. There are 20 such bookshelves in the school. How many books can a * * * hold?
6, 1 Frog eats 98 pests in 1 day. According to this calculation, how many pests can 20 frogs catch in a month (30 days)?
7. There are 38 students in Class One, Grade Three, who hold a relay race, each running 2 laps. The playground is 30 meters long and 20 meters wide. How many meters did the students in this class run?
8. A novel is about 50 pages, with about 25 lines per page and about 30 words per line. How many words are there in this book?
9. A box of 24 pencils costs 90 cents each. Xiaoming wants to buy 2 boxes. How much does Xiaoming have to pay?
10. A building in Xinxing Community 16 floor, with 3 units * *, with 2 households on each floor. How many families live in this building?
On June 1 day, 1 1, the teacher is going to prepare 2 bananas and 1 apple for each student. There are 36 students in the class. How much fruit should be prepared for each class?
12, each box has 16 eggs, each box has 4 boxes, and 6 boxes * * How many eggs do you need?
Fourth, even beyond this problem.
1, four looms weave once a week1568m. How many meters does each loom weave on average every day?
2.360 people are arranged in four phalanxes, each with five columns. How many people are there in each station on average?
The clothing store sells 3 boxes of clothes a day, 6 pieces in each box. A * * * earns 3600 yuan, how much is the average piece of clothing? 4.7 pigs feed 245 kilograms of food a week. 1 pig, how much food does it feed on average?
5. 1 box of moon cakes has two layers, each with four. A factory produces 560 moon cakes every day. How many boxes of moon cakes does this factory produce a day?
6. Grandma keeps 59 hens, 125 cocks, and keeps these chickens in 8 cages. How many chickens are kept in each cage on average?
There are 420 tables in the forest. I want to divide them into seven big groups, each with six columns. How many tables are there in each column on average?
8. 128 pears, 8 in a box and 2 in a box. How many boxes does it take to pack all these pears into cartons?
9. Four bottles/box of cod liver oil and 80 capsules/bottle of cod liver oil. How many capsules is a box of cod liver oil? Grandpa takes two capsules every morning and evening. How many days can grandpa eat a box of cod liver oil?
10, football 90 yuan, basketball 50 yuan. Xiao mingcan bought five footballs with his money. How many basketballs can he buy with this money?
1 1. The kitten caught 168 fish around. How many fish does he catch on average every day?
12, uncle shipped 12 tons of watermelon in three times. How many tons of watermelon can you transport if you transport it eight times?
13, 48 flowers are tied into 1 bundle every 4 flowers. How many bundles can you tie? Send 2 bunches per person on average. How many people can these flowers give?
15. Jinlong Company has 808kg of edible oil, 2kg per bottle. How many bottles can it hold? How many cases can these oils be put in every 4 bottles 1 box?
16. Shirts are packed in the clothing factory, with 4 boxes per box and 7 pieces per box. How many boxes can 560 shirts hold?
17, carp 5 yuan/strip; Carassius auratus 3 yuan/strip; Crab 8 yuan/only.
(1) How many crucian carp can Aunt Wang 42 yuan buy?
(2) How many carp can Aunt Li buy with 1 10 yuan?
My uncle spends as much money on crabs as Aunt Wang and Aunt Li spend on fish. How many crabs did my uncle buy?
18. It takes 20 minutes to make a specimen for each butterfly. The teacher made 10 box of specimens, and 1 box has 6 specimens. How long did the teacher spend making specimens these five days? How many butterfly specimens does the teacher make on average every day?
Verb (abbreviation of verb) travel problem
1.A car travels from A192km for 3 hours, and then travels for 2 hours to reach B. What is the distance from A to B?
2. Distance between Xinxing Primary School and Children's Palace1400m. Wang Jun walks 55 meters every minute from school to Children's Palace. Walk 12 minutes, how many meters to the Children's Palace?
When the car goes up the mountain, the speed is 36 kilometers per hour, and it takes five hours to reach the top of the mountain. When it goes down the mountain, it only takes four hours to return by the same way. How many kilometers does the car travel per hour on average?
Sixth, the area problem.
1, Zhang's remote fence is surrounded by a square chicken coop with a total length of 24 meters. What is the area of this chicken coop?
An apple orchard is 24 meters long and twice as wide. If each apple covers an area of 3 square meters, how many apple trees are there in this apple orchard?
Uncle Wang has a rectangular wheat field. The width of this site is 100 meter, and the length is twice as wide. The average harvest per hectare is 7500 kilograms of wheat. How many kilograms of wheat have been harvested in this field?
4. In order to build his own agricultural products, Uncle Xiao intends to start with the transformation of his own corn base. There is a piece of land 100 hectare, which is planned to be divided into cornfields with a length of 40 meters and a width of 25 meters. How many cornfields can Bobo divide?
5. A vegetable base with a length of 300 meters and a width of 200 meters has a square pond with a side length of 100 meter in the center of the vegetable field. It is planned that the annual income of this vegetable field will be 80,000 yuan per hectare. What is the annual income of this vegetable field?
6. Build a path with a width of 1 m around a square pool with a perimeter of16m. What is the area of this road?
7. The perimeter of a conformal plot is 800 meters, and 75 tons of rice are harvested per hectare. So how many tons of rice have been harvested in this land?
8. A rectangular grassland covering an area of 4 hectares is 250 meters long, so what is its width?
Uncle Li planted pear trees on a hillside of two hectares. Each pear tree covers an area of 8 square meters, and each pear tree needs to collect 400 kilograms of pears. How many Jin can these pear workers receive?
10, a newly-built expressway, 200 kilometers long and 40 meters wide. How many hectares does this highway cover?
1 1. There is a square orchard with an area of 1 hectare. If its edge is extended by 200 meters, how many hectares will the orchard area increase?
12, a rectangular orchard with a length of 1000m and a width of 60m. If the length and width are doubled, how many hectares will the orchard area increase?
13. There are two rectangular brackets. The first one covers an area of 1 hectare, and the second one is150m long and 60m wide. Which of these two plots is bigger? How much bigger?
Seven, enough money.
1. The school will buy 80 sets of desks and chairs, each table 1 10 yuan, each chair 55 yuan. Will the school prepare 2000 yuan enough?
2. Teacher Zhang is going to the sports mall to buy 8 basketballs and 6 volleyballs, each basketball 73 yuan and each volleyball 65 yuan. Is it enough for teacher Zhang to prepare 1000 yuan?
3. The school plans to buy 15 computers and 50 TV sets, each TV set is 1900 yuan, and each computer costs 4,800 yuan. Is it enough for the school to prepare 200 thousand?
The price of each football in the sporting goods store is 68 yuan. Teacher Wang took 500 yuan. Is it enough to buy eight footballs? How many footballs can I buy at most? How much is left?
Eight. Sum-difference problem
1, there are 98 students in Class A and Class B, and Class A has 6 more students than Class B. Please find the number of students in each class. The sum of the length and width of a rectangle is 18 cm, and the length is 2 cm wider than the width. Find the area of a rectangle.
2. Party A, Party B and Party C have three packages of chemical fertilizers, with two packages of chemical fertilizers weighing 32kg, two packages of chemical fertilizers weighing 30kg and two packages of chemical fertilizers weighing 22kg. How many kilograms do you want for each of these three bags of fertilizer?
3. Car A and car B originally contained 97 baskets of apples, and took 14 baskets from car A and put them on car B. As a result, car A had 3 more baskets than car B. How many baskets did each car originally contain?
Nine, multiple problems
1. There are 660 apple trees in an orchard. There are three times as many apple trees as pear trees. How many pear trees are there?
2. The construction site delivered 65 tons of cement in the morning and 15 tons in the afternoon, twice as much as in the morning. * * * How many tons of cement were delivered this day?
3. A batch of ***250 tons of cement arrived at the construction site. The first week used 78 tons, and the second week was twice as little as the first week, 15 tons. How many tons of cement are left in this batch?
4. The flower shop sold 230 roses on Sunday, 15 more daffodils than on Sunday, and the roses were twice as many as daffodils. How many roses did it sell?
The students visited the Science and Technology Museum. There are 45 students in grade four, 0/2 students in grade five/kloc, and how many students in grade two?
X. number of copies
1, known? 2 is it? 1 twice. 3 What is it? Six times of 1? 1、? 2、? The degree of 3. (Figure 1)
2. known? 1=? 2=? 3. The sum of all angles in the drawing is 180? , find the degree of the maximum angle. (Figure 2) (Hint: For both questions, the total number of copies is calculated first, then the degree of the minimum angle, and finally the corresponding angle)
XI。 Price problem
1, each suit 120 yuan. How much does it cost to buy five sets?
2. The school bought three identical repeaters, which cost 420 yuan. How much is each repeater?
Twelve. Preferential problem
1, each 48 yuan electric kettle, buy 3 get free 1, buy 4 at a time, how much cheaper is each?
2. Every tree seedling 16 yuan, buy three and get one free.1How many trees can 76 yuan buy?
3. Movie tickets 15 yuan each, buy ten and get one free. Teacher Wang takes 135 students to buy tickets. How many tickets do you need to sell at least?
Thirteen, the problem of finding the number of angles
1, a right triangle with an acute angle of 38? What is the other acute angle?
How to improve the efficiency of mathematical calculation
1 improves the writing speed and quality of numbers.
There are children who have just entered primary school and have good logical thinking ability. They answer questions clearly in math class and have a high level of analysis. However, the math test scores are always not high, mainly because of poor writing.
First, slow; Second, the figures are not clear. For example, 0 is often written as 6, 5 as 3 and 4 as 9. This type of children can improve their writing speed and quality through careful training.
Training methods:
Spend five minutes every day writing numbers and mathematical symbols "+- 1234567890=" (as a group).
Training requirements:
Remember 5 minutes, how many groups can write neatly, and praise if there is progress.
Strengthen oral arithmetic practice
In the first grade of primary school, I mainly practice addition and subtraction within 20, look at the formula and write the answer.
Set a time (say, five minutes) to write down how many problems your child can complete. In the second and third grades of primary school, I mainly practice multiplication and division. The method is as above. In the third and fourth grades of primary school, practice oral arithmetic of multiplying one number by two numbers. Write 20 small questions every day, such as 12? 5= 18? 6= 17? 9= This is dozens of times. Increase it to more than twenty times in the future, and record the completion time and correct rate.
In addition, remember the relationship between some commonly used numbers. Such as the reciprocity of common fractions and decimals. Such as pi 1? Before nine o'clock? , 16? ,25? ,36? Wait a minute. This is mainly practiced in the fifth and sixth grades.
The above oral arithmetic exercises are carried out step by step according to the progress of children's mathematics learning.
Firmly grasp the basic knowledge
Basic knowledge and skills of mathematics must be solid. For example, children must be able to master the knowledge of triangles, which have three sides and the sum of the three internal angles is 180 degrees. Triangle can be divided into acute triangle, right triangle and obtuse triangle according to its angle; Divided by sides, triangles include isosceles triangles and isosceles triangles include equilateral triangles. Can draw the height of triangle, master the area formula of triangle (know the bottom and height to find the area, or know the area and height to find the bottom, and so on). ). Only by firmly mastering the basic knowledge can we carry out expansion exercises on this basis.
2 "Improve reading speed and analytical ability"
Let children use and observe mathematics in their lives.
Some children have poor math learning ability and divergent thinking. You can't turn around when you study math, for example, when you do a first-grade topic, there are five birds in the tree, three fly in and a few * * *. The child's formula is 8-3=5, and the child doesn't know what to ask him to do. Doing a problem is like guessing a riddle. He doesn't know the reasoning.
The main problem is that children ignore the purpose and significance of solving problems, as if they are not enlightened and do not like thinking (maybe they don't know where to think).
The key to this problem is that children haven't figured out how to learn mathematics, which means that learning mathematics is still in the stage of memory and imitation.
The way to solve this problem is to cultivate children's interest in mathematics and thinking about problems in life. Parents seize the opportunity to design such questions for their children in life.
Learn to analyze the quantitative relationship of problems.
Some children shouted "Mom, how to do this problem?" The parents said, "Have you seriously considered it?" He said he thought about it, but he couldn't think of it. Before his parents gave him a hint, he suddenly understood. This hint is only a little. It stands to reason that he should be able to think of it, but the child is unwilling to think deeply.
There are many reasons for this phenomenon. The main reason is that children do not fully explore the relationship between the conditions of the problem when solving the problem. Giving hints is not the best way. A more effective method is to guide children to deeply analyze every condition of the problem.
When guiding children to solve problems, what are the conditions for asking children to analyze this problem first?
Secondly, let the children talk about the conditions of this problem.