127×3 6
X185 Please tell me how you worked it out. 2. Say the meaning of each score below. A
The peanut yield is 4 1. The best wheat.
The speed of the train is 3.4 times that of the car. The students answered and the teacher demonstrated in the media. what do you think? What do you think of the unit "1"? 3. Mother Rabbit chose 12.
A mushroom. She gave four-thirds of these mushrooms to the children. How many mushrooms did the children get? (Note: Excerpted from page 7 1 in the second volume of Grade Three) Retell yesterday's story with the students, and make it clear that the solution to this kind of problem at that time was: divide 12 mushroom into four parts on average, and rabbit into three parts, namely 1 2 ÷ 4× 3 Teacher: Review the meaning of fractions, and solve the practical problem of the fraction of a number by integer multiplication and division, so as to prepare for further study and stimulate students' interest in knowledge. Second, explore new knowledge and learn to think 1. Example 2: In order to celebrate the National Day, Xiaofang made 10.
Silk flower, of which 2 1
Red flowers, 5/2 are green flowers.
(1) teacher's doubts: 2 1, 52
What watches do you have? (take 10 silk flower as the unit "1", and the number of safflower is 10.
A silk flower is 2 1, and the number of green flowers is 52 10 in silk flower.
)
Teacher: What questions will you ask?
Teacher: Let's choose a few questions. The media showed us: (1) How many red flowers?
(2) Question: How many red flowers are there? How many red flowers do you need? Which score is related to, (21); Ask for red flowers.
Whose 2 1 is the number of flowers? That is, whose unit is 1, that is, 2 1 and 2 10 on the blackboard.
1
It's safflower. This question is yours.
Can it be solved?
Teacher's blackboard: 10÷2=5 (flowers) 10× 1/2=5 (flowers)
(3) Doubt: What can you find by comparing two different calculation methods? Doubt: Why do multiplication and division have the same result? Show me question 2: How many green flowers are there?
The teacher wondered: How many green flowers are there?
2
? Circle in the picture.
Question: How to answer?
Blackboard: ① 10÷5×2=4 (flowers)
② 10×5
2
=4 (flowers)
The teacher wondered: What is the connection between these two different calculation methods?
The second formula to guide students to understand is to divide the flowers of 10 into five parts.
Therefore, the internal meanings of the two questions are unified: they are all seeking the five of a number.
2
how much is it?
2. Summary: What have you gained by studying these two exercises?
Media presentation: Find the score of a number, which can be calculated by multiplication.
Question: 10×2 1, 10×5.
2
What do you mean?
Dialogue: Multiplying a fraction with an integer means not only finding the sum of several identical addends, but also finding the fraction of a number.
Design intention: By observing examples and analyzing information, students should think independently first and then cooperate with others to find a solution to the problem, that is, to explore the method of calculating the score of a number by multiplication, to mobilize students' thinking enthusiasm, cultivate students' ability to analyze and solve problems, and enhance students' sense of cooperation.
Third, consolidate exercises and expand the application of 1 Complete "Exercise 1" p40 (1) and complete 1 question.
(2) Complete the second question.
Teacher doubts: 5
2
How many meters is the root number and how many meters is the 43 root? How do you understand them?
2. "Muyangtao" is a traditional specialty in eastern Fujian and a famous fruit with local characteristics with the most development potential.
One. 48 yuan per kilogram, Qingqing is a kind-hearted teenager who respects the elderly and loves her relatives. She bought three with her pocket money.
2
Kilogram mu
Carambola is filial to grandma. How much does she have to pay?
3. A whole note needs 4 beats, and the duration of a sixteenth note is 16 of the whole note.
1
What is the duration of the sixteenth note?
4. The poem "Spring" has 30 words, of which "Spring" accounts for 52% of the whole poem.
What are the words "spring"?
Make it clear: the number of "spring" = the number of words in the whole poem ×5.
2
After the answer, the courseware shows the poem "Spring" to make students beautiful.
Read it carefully.
Spring water and spring pool are full, and spring grass grows in spring. Spring trees bloom, and spring rain is accompanied by spring breeze. Spring birds make spring scenery, and spring people are busy with spring ploughing.
Design intention: Mathematics practice is boring and monotonous, and students are easy to get tired. Strengthening the integration between disciplines, integrating mathematics with "Morality and Society", "Chinese" and "Music" can open students' eyes. For example, combining exercises with a catchy poem will help students learn mathematics poetically, not only stimulate their enthusiasm for learning mathematics, but also make them clear the value of mathematical knowledge and cultivate their sentiment.
3. In the Chinese composition class, the teacher assigned a composition. As soon as the bell rang, a student found that he had only written 100. Seeing the bad place, he had a brainwave and wrote "four times the above content" in the last line of the article. A few days later,
The composition was handed out, in the position of the score, "Your composition score is:/kloc-4 out of 0/00."
1
"Excuse me, teacher?
How many words should I write in my composition? What is the score of the student's composition? Later, he rewrote it, and the teacher thought it was better than the original.
Eighteen times, so I gave him a reward and announced the final score of 5 for the first time.
18
What is the final score of the students' composition?
Ask the students to find the company "1" first.
Concluding remarks: Finding multiples of a number is essentially the same as finding fractions of a number. Generally, when the multiple exceeds 1, it is called a multiple, and when the multiple is less than 1, it is called a fraction. But when it exceeds 1, it is also acceptable.
Suppose the multiple is a fraction, and this fraction is a false fraction. For example, 5 18.4 times can be expressed as a fraction of 1.
four
, classmates
Son, in the final analysis, what is the score of a number? What method is used to calculate? (multiplication)
Fourth, assign homework and expand. Do you want to challenge?
Xiaoguang read a book of 120 pages. On the first day, he read 3 1, and the next day, he read 5 pages.
2
I saw it in two days.
How many pages?
Attached book design:
Find the fraction of a number.
(by multiplication)
12
43
12÷4×3=3×3=9 (flowers) 10 3 1
① 10÷2=5 (flowers)
② 10×3 1
=5 (flowers)
65438+52 00 flowers in total
① 10÷5×2=4 (flowers)
② 10×5
2
=4 (flowers)