Textbook page 965438 +0, page 92, for example 1, exercise 1-3 in 2 1.

Second, the teaching objectives:

1. Understand decimals in combination with specific contents, understand the actual meaning of decimals in yuan and meters, know decimals, and read and write decimals.

2. Know that a few tenths can be expressed with one decimal place and a few percent can be expressed with two decimal places.

3. Through the preliminary understanding of one and two decimal places, let students understand the application of decimals in real life, cultivate students' ability of observation, generalization and analogy, and love life and mathematics.

Third, the teaching emphasis and difficulty:

1. Understand the meaning of decimal and how to read and write decimal.

2. express a few yuan, cents, meters and centimeters as decimals of yuan and meters.

Fourth, teaching preparation: courseware

Verb (abbreviation of verb) teaching and learning process

(A), create a situation, resulting in problems

1. Dialogue: Classmate, a child is in trouble. Would you like to help? Xiaohong and her mother go shopping in the supermarket. She doesn't know the price list (supermarket items and prices displayed on the small blackboard or courseware).

2. Observe the commodity price and name the commodity. (Answer the blackboard with the students: 5.98.0.85 and 2.60)

3. Comparison: What are the characteristics of these price tags in the supermarket?

(2) Discuss communication and solve problems.

Know decimals.

1. student report comparison result: there is a dot in the middle of the number. Clear: this. " It's called the decimal point, and it's pronounced "dot" when you read it.

2. Summary: Numbers like 5.98, 0.85 and 2.60 are called decimals. (Teacher writes on the blackboard: decimal)

3. Theme: Today, in this class, we will learn decimals.

4. Say: Have you ever seen decimals in your life? Where have you seen it? Tell me about the decimals you have seen.

Students list decimals, for example, the price of a pack of instant noodles is 1.50 yuan, and the temperature measured when you have a high fever is 38.5 degrees.

Mechanical pencil's refill is: 0.5mm, and my height is:1.38m. ..

5. Read the price on the trademark (emphasize the unit)

(1) Can you read these decimal places? Who will try to read it? If a student makes a mistake, the teacher will give it directly, and then let the student who makes a mistake try to read it. )

(2) Discussion: Is there a difference between the left half and the right half of the decimal?

(3) Summary: We take the decimal point as the boundary, and the numbers before the decimal point are still read according to the integer reading method we learned before, and the numbers after the decimal point only need to read the numbers on each digit in turn.

(4) Read out the decimals in turn and complete the blackboard writing: 5.98? Five dollars and ninety-eight cents. 0.85? 0.85? 2.60? Two point six zero

(5) Read decimals again, and read and listen to each other at the same table.

Understand the meaning of decimals representing prices.

1. Explore the meaning of these decimals in life. (Show the table in the book)

(1) Q: How much is 5.98 yuan? Clear: 5.98 yuan is 5 yuan's 9.80 points. ……

(2) Explore the characteristics of decimals representing prices. Are there any tricks when looking at the price?

Clear: there are several elements before the decimal point, the first digit after the decimal point indicates several angles, and the last digit indicates several points.

(3) Students' trial reading: the price of schoolbags is 58.95 yuan; Pencil price 12.00 yuan, study table price 128.09 yuan.

The meaning of the decimal representing the length.

1. Guess: 0. 1 How long is the meter?

2. Question: What exactly does the decimal of the length mean? Ask students to teach themselves the textbook P89, think about these two questions and see who has learned the most knowledge.

Think about it: (courseware demonstration)

(1) decimeter. How to write centimeters as a decimal of meters?

(2) What is the relationship between decimals and the scores we have learned before?

3. Students teach themselves textbooks and exchange feedback.

How to write decimeters in (1) meters as decimals?

1 meter is divided into 10 parts on average, each part is 1 decimeter, 1 decimeter is meter, or it can be written as 0. 1 meter.

(2) blackboard writing: 1 decimeter = 0. 1 meter

Note: These three can all be used to represent the length of the same line segment, so we connect them with an equal sign.

(3) It is also concluded that 3 decimeters = meters = 0.3 meters.

(4) List of students. (? ) decimeter = meter = () meter

(5) Students explore how centimeters are written as decimals in rice.

? Teachers teach themselves in combination with students. Feedback helps students organize and complete:

1 cm = m = 0.0 1 m？ 5 cm = m = 0.05 m.

18cm = m = 0. 18m(？ )cm = m =(？ ) meter

5. Observation and comparison: Please observe the above two sets of equations carefully. What did you find? (Give students some time)

(Guide students to observe that a few tenths of a meter can be rewritten to one decimal place, and a few hundredths of a meter can be rewritten to two decimal places. )

Use decimals to express height.

1. Dialogue: Our height is also expressed in length units. Show it: Dong Wang is 1.30 cm, and the decimal is () meters. what do you think? (blackboard writing: 1 m 30cm =1.30m)

2. Then who can tell me his height? Can you express it in decimals?

Students say their height and use decimals to communicate at the same table. )

3. Question: What does 1 to the left of the decimal point mean for height? What does the number on the right mean?

4. Description: In fact, where else can you see it besides decimals used to express price and length? (roll call) The teacher also found some! Take it out and read it (Courseware or Small Blackboard)

The eraser is 0.03m long and 0.02m wide; Speaker 1.5m, 0.85m wide and 0.5mm thick in pencil lead.

5. Summary: Through the students' study just now, we know that a few tenths can be converted into one decimal place and a few percent can be converted into two decimal places. This is an important discovery. Now let's do some exercises to see who can apply this discovery.

(3) Consolidate application and improve internalization.

1. Find and read decimals.

Narrator: There is going to be a dance in the decimal kingdom recently, but the king found some integers mixed in. Please distinguish them with our class's eyes.

18 20. 1 9 0.56 106

2. Do it: P92? Let the students fill in independently and give feedback collectively.

3.P94 Exercise 20 questions 1. Let the students read aloud to each other at the same table.

Think about it and say it.

The teacher's mobile phone fee this month is 85.50 yuan, which is () yuan () jiao.

Yao Ming's height is 226 cm, which is () meters.

Xiao Ming bought a box of milk, and spent two 1 yuan and a nickel. The box of milk was RMB ().

(Note that students are asked to compare 2.05 and 2.5 here. )

(4), review, reflection, promotion.

What did you learn from this class today? What skills have you learned?