Teaching content: page 66 of the fifth grade (Volume II) of the experimental textbook.

Teaching objectives:

1. Let students explore and understand the practical problem of finding a score with a number by using the meaning of the score. Through the process of exploration, they can further deepen their understanding of the meaning of music score. Perceived score can not only represent the relationship between the part of a quantity and the whole, but also the relationship between two quantities.

2. Develop students' sense of numbers, enhance their awareness of independent exploration and cooperation, and appreciate the application value of mathematics.

Teaching emphasis: explore and understand the method of finding the score of one number to another.

Teaching difficulty: determine the number of units "1".

Teaching process:

First, review the introduction:

1, and the relationship between the following colored parts and the whole is expressed as a fraction:

2. Introduction of the topic:

Show courseware (red ribbon and yellow ribbon map)

Teacher: What do you know from the picture?

What math questions would you ask? Questions may include:

(1) How many times is the yellow ribbon?

(2) How much is the yellow ribbon? (Courseware demonstration)

In response to question (2), the teacher asked: How was this problem solved? what do you think?

Idea 1: Divide the yellow ribbon into three equal parts, and the red ribbon is as long as one of them. So the length of the red ribbon is 1/3 of that of the yellow ribbon.

Idea 2: 1/3 of the yellow ribbon is as long as the red ribbon. So the length of the red ribbon is 1/3 of that of the yellow ribbon.

Teacher: What is the unit "1" here? (Answer by name)

After the students answer, the teacher draws a line under the "yellow ribbon" and writes on the blackboard: Unit "1"

Teacher: If the yellow ribbon becomes shorter, how much is the red ribbon now? Why? What unit is "1"?

If the yellow ribbon becomes longer and the red ribbon remains the same, how much is the red ribbon? Why? What unit is "1"?

Summary: It seems that the score can not only express the relationship between the part and the whole, but also express the relationship between two different quantities. Today we study the relationship between two different quantities.

Second, explore the problem

1, showing an example.

Jia Xiaoxin has 7 geese and 10 ducks. What is the number of geese?

Teacher: What information do you know from the topic?

In response to the students' answers, ask: What is the question, that is, a fraction of 65,438+00 is seven? Think that 7 is only a fraction of 10. (7/ 10)

Teacher: What do you think?

Idea 1: Take 10 ducks as a whole and divide them into 10 parts on average, each part is 1, 1 just the whole1/0, and 7 ducks are 7//kloc-0 of the whole.

Idea 2: Graphical representation, analyzing that 7 is the whole 7/ 10.

Teacher courseware demonstration:

The red circle stands for "goose" and the white circle stands for "duck". The "duck" is regarded as the unit of 1, which is divided into 10 on average, each of which is only110, and seven of them are its 7/ 10.

Teacher: According to the relationship between fraction and division, can you rewrite 7/ 10 into a division formula?

The student said that the teacher wrote on the blackboard:

7÷ 10=7/ 10

Contrast: Just now, according to the meaning of score, drawing method and column formula, the number of geese is 7/ 10 of ducks. Which method do you think is simpler?

2. Exercise: Jia Xiaoxin planted 5 peach trees and 9 pear trees. What is the number of peach trees?

When giving feedback, ask the students to say who they regard as the unit "1", and who compares with whom?

3. Build a model:

Contrast: What are the similarities?

(1) There are 7 geese and 10 ducks in Jia Xiaoxin. What is the number of geese compared with ducks?

(2) Five peach trees and nine pear trees have been planted in Jia Xiaoxin. How many peach trees are there compared with pear trees?

Similarities:

Conditions and problems: There are two different quantities, both of which are seeking the score of one quantity.

Solution: All are calculated by division.

4. Reveal the theme: Find out the score of one number to another.

Third, expansion and application

1 Grade 5 students participated in mountaineering activities, including 36 boys and 9 girls.

(1) What percentage of girls are boys?

What is the proportion of girls in this class?

(3) What is the proportion of boys in the class?

Master Wang produced 200 parts, and two of them were unqualified after inspection. How many parts are qualified?

3. A book has 72 pages, and Xiaojun has read 53 pages. How many pages have you read in this book? How many pages are left in this book?

There are two piles of goods on the dock, the first pile is 29 tons and the second pile is 32 tons. What is the quality of the first batch of goods? What is the mass of the second pile of goods in the total mass?

Teaching material analysis:

The content of this section is based on a summary of the meaning of fractions. Let students use the meaning of fractions to explore and understand the practical problem of finding the fraction of one number is another. Through teaching, students can further understand the meaning of scores. Understanding score can not only represent the relationship between part and whole, but also the relationship between two related quantities, which can expand one's understanding of score and appreciate its application value.