1. Understand and master the quantitative relationship of "What is the percentage of a number" and correctly answer the practical question of "What is the percentage of a number".

2. Correctly analyze the quantitative relationship in the topic and improve the ability to solve practical problems.

3. Let students feel the close connection between mathematics and life, and apply what they have learned.

Teaching emphasis: understand and master the quantitative relationship of "what is the percentage of a number".

Teaching difficulty: correctly analyze and answer the practical question "what is the percentage of a number"

Teaching aid preparation: small blackboard.

Teaching process:

First, review the import (displayed on the blackboard):

1. A pile of coal weighs 2500 tons and uses 3/5. How many tons were used?

2. The collection of books in the school library is 1400 volumes, which has increased by 3/25 this year. How many books are there in the library now?

Methods: Let the students draw a line chart for analysis, then calculate it with a column chart, and then modify it collectively.

Second, the new curriculum teaching:

1, revise (1): If you changed 3/5 to 60%, would you still answer?

(1) Give it a try, students.

(2) Collective communication and summary of problem-solving methods.

2. Change review (II): Change 3/25 to 12%. Ask the students to answer independently, and then revise collectively.

There are two solutions to this problem: a.1400+1400×12%.

b . 1400×( 1+ 12%)

3. Compare the similarities and differences between the two methods.

Third, consolidate the exercises:

1, a bag of 240 kilograms of rice has already eaten 25%. How many kilograms is left?

2. There are 120 girls in the choir, with 20% less boys than girls. How many boys are there?

3. The first question in Exercise 22.

4. "Do it" on page 93.

Fourth, the class summary:

5. Homework: Exercise 22 #2~#7 Source: Science Bar, the best resource.