Teaching Content: Compulsory Education Curriculum Standard Experimental Textbook (Jiangsu Education Edition) Grade Two (Volume II)

Teaching purpose:

1. Know the length units decimeter and millimeter in practice, and establish the length representation of decimeter and millimeter. Be familiar with the length units of millimeters and decimeters, and initially establish the length concepts of 1mm and 1mm, and know that1cm =10 mm1mm =10 mm.

2. The length will be expressed in appropriate units, and simple length measurement will be carried out.

3, through hands-on operation, cooperation and communication and other learning activities, improve the awareness of participating in learning and experience the fun of learning.

Teaching focus:

Make students familiar with the length units of millimeters and decimeters, and initially establish the length concepts of 1mm and 1mm, knowing that 1cm = 10mm =10 mm =

Teaching difficulties:

Help students to establish the concepts of length of 1 mm and 1 decimeter, form representations, deepen their understanding of the concepts, and correctly express the length of objects by using the concepts.

Teaching preparation:

Student ruler, meter ruler, courseware, physical projection

Teaching process: 1. Analysis of teaching content;

The understanding of millimeter and decimeter is the content of measurement in space and graphic knowledge. The requirement of "Curriculum Standard" for measurement is to closely link measurement with students' practical activities and realize the importance of establishing a unified measurement unit. This part of primary school mathematical measurement is divided into two stages. The first stage is to know rice and centimeters in the second semester of senior one; The second stage is to know decimeter, millimeter and kilometer in the second semester of Senior Two. The main content of this lesson is to know the knowledge of millimeter, decimeter and kilometer, which is arranged in the second section.

Arrange practical activities in the textbook of this lesson to help students understand the practical significance of millimeters and decimeters, establish the concepts of 1 millimeters and 1 decimeters, understand the relationship between millimeters and centimeters, decimeters and meters, decimeters and centimeters, and initially learn how to measure objects in millimeters and decimeters. In addition, through the teaching of this unit, students can have a more complete understanding of the length unit and the progress between two adjacent units.

Second, the analysis of learning situation:

In the previous study, students have already known the length units of meters and centimeters, initially understood the importance of using uniform length units in measurement, and mastered some basic measurement methods, such as aiming one end at the scale 0, and the scale pointed by the other end is the length of the object. These measurements are limited to whole centimeters. In daily life, students are exposed to meters and centimeters, for example, the playground is about 200 meters long and the height is 1.38 cm. Although there is less contact with millimeters and decimeters, now students can acquire knowledge from various channels. It's not that they don't know millimeters and decimeters. Some students already know the names of millimeters and decimeters. However, after actual understanding, it was found that most of these students could only name the company. As for the length of 1mm and 1mm, they haven't established the correct representation in their minds, and they don't know why they use these companies. They only have a vague understanding of millimeters and decimeters, and need in-depth study and exploration.

Third, the design concept and my thinking:

The specific goal of the first section of the mathematics curriculum standard, space and graphics, points out that "the process of measuring the length of an object is experienced in different ways in combination with the actual life." In practice, we can understand the meaning of meters and centimeters, recognize decimeters and millimeters, perform simple unit conversion, and properly choose length units. " People often encounter measurement problems in real life, and the research on measurement shows the value and practical application of mathematics.

(1) Create a life situation close to students' reality, infiltrate students with the idea that length units come from practice and apply them to practice with the help of specific measurement activities, and cultivate students' innovative consciousness and ability to apply what they have learned to solve practical problems.

(2) Further, through students' experience of measurement, I realized the necessity of establishing measurement units.

(3) In the process of measurement, gradually understand the actual meaning of the measurement unit, and appropriately select the length unit to further cultivate the space concept and hands-on operation ability.

(4) We can estimate the length of some objects and further develop the estimation consciousness.

In short, in this class, I use centimeters as a link (centimeters are the most common unit of length in life) to connect meters, decimeters and millimeters. With the help of measurement, the length expressions of 1 decimeter and 1 millimeter are established, and the forward speed between length units is identified. Guide students to actively participate in activities, so that students can perceive, experience and establish rich representations through activities such as observation, scale, hand measurement, gesture comparison and understanding of examples in life. Let students strengthen the representation in the process of estimation, comparison and verification, so as to gradually form the concept of space.

Fourth, the lesson plan:

Teaching content: understanding of millimeter and decimeter. (Beijing Normal University Edition textbook, Grade Two, Volume 2, Page 42)

Teaching objectives:

1. In surveying activities, the practical significance of millimeters and decimeters is clarified, and the length expressions of 1 mm and 65438+ decimeters are established.

2. Grasp the forward speed of 1m = 10 decimeter, 1 decimeter = 10 cm, 1 cm = 10 mm in practical activities such as observation, guessing and verification.

3, in the actual measurement activities, initially learn to choose the appropriate length unit to measure the length of the object.

4. Gradually realize the close relationship between mathematics and real life, and initially cultivate the consciousness of solving practical problems.

Teaching focus:

Understand the length units of millimeter and decimeter, and initially establish the length concepts of 1mm and 65438+ decimeter.

Teaching difficulties:

Correctly understand the relationship among millimeter, centimeter, decimeter and meter.

Teaching preparation:

Courseware, ruler, coin, magnetic card, etc.

Teaching process:

First, the introduction of the situation, causing thinking

Teacher: (showing a new children's drink on the market) Can you estimate the height of the drink box first, and then measure its height?

Students report the measurement results.

(It may be 8 cm, 8 cm and a half, 8 cm and 5 grids, 8.5 cm, 8 cm and 5 mm, etc. )

Teacher: Students, when measuring, the part over 8 cm is not enough 1 cm. When we can't accurately express the length of the measured object in centimeters, we need to use the length unit less than centimeters: millimeters.

[Design intent: Through the measurement activities of small beverage boxes, help students realize the practical significance of millimeters on the basis of existing experience. ]

Second, explore and solve problems independently.

(1) Understanding millimeters

1. Know the millimeter and establish the representation of 1 millimeter.

Teacher: What do you know about millimeters? How to say 1mm on the ruler? The length of the smallest square on the ruler is1mm. ) Show your deskmate what you are looking for1mm.

Let's take an experience trip: 2 minutes, look in the bag, look, touch, pinch and find 1mm, and then measure and verify. See who found more?

Health 1: Through measurement, I found that the thickness of 1 cent coin is about1mm.

Health 2: Through measurement, I found that the thickness of 1 magnetic card is about1mm.

Health 3: Through measurement, I found that the width of the word is about1mm..

Health 4: Through measurement, I found that the thickness of 1 disk is about1mm. ……

Teacher: Can you remember how long 1mm is in your own way?

(Students pinch 1 CD or 1 penny or 1 magnetic card to establish the concept of 1mm space. )

[Design intent: After helping students to initially establish the representation of 1mm, let students find the representation of 1mm independently, give full play to students' initiative, independence and initiative, and construct the representation of 1mm in their minds. ]

2. Contact with real life and learn more about millimeters.

Teacher: In our life, millimeter is a commonly used unit of length. Do you know where millimeters are used? (Courseware) Why should the length, height or thickness of these objects be measured in millimeters?

Student: Millimeter is a more accurate unit of measurement.

[Design Intention: Finding the millimeter in life will help students to further understand the role of millimeter and understand the close relationship between mathematics and life. ]

3. Explore the relationship between millimeters and centimeters.

Teacher: What's the relationship between millimeters and centimeters? How to verify this guess?

The square in the middle of students 1 cm.

Re-verification (courseware enlarged scale diagram)

Teacher: What conclusion can you draw?

Voice:1cm =10mm1cm =10mm.

[Design Intention: In practical activities such as observation, guess, verification and hands-on operation, I have found out the propulsion rate of millimeters and centimeters, and I know 1cm = 10mm. ]

(2) Understand decimeter

1. Introduce decimeter and learn the relationship between decimeter and centimeter.

Teacher: Guess how long the straw of this beverage box is? Why?

Take out the straw from the schoolbag. Each student estimates the length first? And actually measure it?

Health: 1 0cm is1decimeter. 1 decimeter is10cm.

2. Establish the expression of 1 decimeter, and actually estimate it.

Teacher: Please look for 1 decimeter on the ruler and try to remember how long it is.

The length between 1: 1 cm and 10 cm is 10 cm.

The length between 2: 20cm and 30cm is10cm.

The length between 3: 15cm and 25cm is 10cm. ……

Teacher: Can you estimate the approximate length of this table?

Why use decimeter as the unit of measurement?

Health: millimeters and centimeters are small, meters are too big, and decimeters are more suitable.

[Design intent: Students perceive the length of 1 decimeter through practical operations such as measurement and counting, and master the progress of decimeter and centimeter while establishing the length representation of 1 decimeter. ]

3. Study the relationship between decimeter and rice.

Teacher: We know decimeter. Please compare gestures with 1 decimeter, gestures with 1 meter. Guess how many decimeters 1 meter is long?

Health: 10 decimeter is 1 meter.

Teacher: Use this meter ruler to count the times of verification. How else can you verify it?

Student: You can calculate 1 m = 100 cm, 1 decimeter = 10 cm, so 1 m = 10 decimeter.

Teacher: What's the relationship between meter and decimeter?

Health: 1m = 10 decimeter 1m= 10dm.

Three. abstract

Teacher: In this class, we learned decimeter and millimeter, plus the original meter and centimeter, which are all units for measuring length. How long does it take to draw 1 mm, 1 cm, 1 decimeter, 1 m with gestures? Please line up from big to small by gesture? Can you find the relationship between these units of length? (decimal)

[Design Intention: By queuing the learned length units from big to small, students can have an overall understanding of these length units, further consolidate the progress between these length units, help students form a knowledge system, use fingers to represent length units, use more vivid things to assist students in memory, improve their interest in learning, and establish a preliminary concept of space. ]

Fourth, consolidate practice and expand application.

Naughty diary (courseware).

Friday, April 6, 2007 is fine.

This morning, I got up from a 2-meter-long bed, picked up a toothbrush with a length of 1 cm, brushed my teeth, washed my face in a hurry and had breakfast. On my way to school, I saw a 2 cm tall tree broken by the wind, so I quickly found a rope 1 cm long to tie the small tree. I ran to school, and the teacher was already lecturing in the classroom. I quickly pulled out a pen with a length of 1mm and a notebook with a thickness of 4m from my schoolbag and took notes carefully.

Ask two students to discuss the revision.

Verb (abbreviation for verb) assigns homework.

1. What other units of length do you know? (kilometers, feet, inches, feet, nanometers, etc.). ) You can go online to learn relevant knowledge and consult your parents. You can show the relevant knowledge you have found in class, and everyone can learn from each other.

2. The second task is for everyone to freely choose objects and measuring tools after class, estimate first, choose appropriate units in actual measurement, and record the measurement results. The teacher recommended a form for you.

Name of object and measuring position

Estimated length (height or thickness)

Actual measurement results

Blackboard design:

textbook

Understanding the teaching content of decimeter and millimeter is the knowledge of the second grade of Soviet education. The study of this lesson is based on the fact that students have learned meters and centimeters. Through learning, students know the student ruler and meter ruler, and can count the big squares and small squares on the student ruler. They know that 1 cm is 10 cm, 1 m = 100 cm. Therefore, the teaching goal of this lesson is: 1, know the new length units decimeter and millimeter, and make gestures for 1 decimeter and 1 millimeter. 2. Master 1 decimeter = 1 0cm,1cm =10mm ... 3. Cultivate students' interest in learning, let students actively participate in teaching activities and use what they have learned to solve problems in life. Understand the new length units decimeter and millimeter. Teaching difficulties: understanding 1 decimeter = 1 0cm,1cm =10mm.

Second, teaching methods and learning methods.

1, visual demonstration

Through vivid courseware demonstration, let students understand the new length units decimeter and millimeter through observation and comparison, and realize that decimeter = 1 cm and1cm =10 mm.

2. Teacher-oriented and student-centered.

Under the guidance of teachers, stimulate students' interest in learning, fully mobilize students' enthusiasm for learning, let students learn in activities, and gradually understand 1 decimeter and 1 cm.

Third, the teaching process

1, review and introduce new ideas

(1) The physical display platform shows a student ruler.

Question: Students, the teacher has a student ruler here now. Can you tell us something about this student ruler?

Design goal: Let the students recall what they have learned about meters and centimeters, and know that the students' scales are divided into big squares and small squares. The big grid of 1 is 10. Each 1 grid is 1 cm.

(2) Draw a line segment with the length of 10 cm.

Question: Can you guess how long the teacher intends to introduce this line segment in one sentence?

Design goal: set up doubts and stimulate students' interest in learning.

(3) Today, we continue to learn the unit of length.

2. Newly awarded

(1) Show Scenes (Courseware Demonstration) Teaching Decimeter

Question: From the little boy's introduction, did you find out who the new length unit is? (student: decimeter)

Activity 1:

Requirements: 1. Find out how far 1 decimeter is from your ruler.

2. Hand-painted length of 1 decimeter.

Design goal: Understand the new length unit decimeter. Feel how long 1 decimeter is.

Activity 2:

Requirements: Draw a line segment with the length of 1 decimeter on your own notebook with a ruler.

Question: How is the line segment of 1 decimeter drawn?

Exercise: Determine whether the picture below is 1 decimeter. (The courseware shows the drawing method, from scale 5 to scale 1 15)

Activity 3:

Requirements: 1, observe the meter ruler in groups of four.

2. Count the number of 1 decimeter.

Back to the beginning: I introduced it like this. The length of this line segment is 1 decimeter. Did you guess right?

(2) Continue to teach millimeter (courseware display scene)

Introduction: Teacher Eggplant is measuring the thickness of our math book. You see, it's less than 1 cm. At this time, we need a new length unit less than cm-mm. Let's listen to how the eggplant teacher introduced the millimeter as a length unit.

Courseware demonstration: the length of each cell in the middle of 1 cm on the ruler is1mm.

Activity 1:

Requirements: 1. Please point your pen at your ruler and count. 1 How many squares are there? Blackboard: 1 decimeter =10cm

Please draw the length of 1mm by hand.

(3) courseware appreciation 1mm

Do you know that the length and thickness of something can be measured in millimeters?

Students discuss, say and say.

Fourth, consolidate practice.

1, and fill in the appropriate number in ()

1 decimeter = () cm 1 cm = () mm

3 decimeters = () cm 3 cm = () decimeters

30 cm = () decimeter 50 mm = (decimeter

Design goal: to enable students to master the simple unit conversion between decimeter and millimeter. Prepare for the following study.

2. Complete thinking and action 2

Students finish independently

Communication: What do you think? As long as what the students say makes sense. )

Teaching objectives: first, understand the different methods to solve this problem; The simple method of the second number, there is a long line segment in the middle of each large cell, and each large cell is divided into two parts on average, each part is 5 small cells or 5 mm

3. Take () days as the appropriate length unit of life.

1 tree height 2() 2 phone card thickness 2 () 1 bed length 2 ()

1 pencil length 2 () A nail length 2 () A cucumber length 2 ()

Design goal: to connect with life and let students deepen their understanding of the four length units through practice. Further consolidate the length units and know where each unit is used.

4. Group measurement

Requirements: 1, two people at the same table 1 team work.

2. Measure the height of the desk and chair with a ruler. How many centimeters and decimeters are close to each other?

3. Make records and communicate with the whole class.

5. Think and do 6 when you are finished.

The courseware shows three line segments. Which line segment do you think is the longest? (Students solve it by themselves)

The whole class exchanges ideas, one is estimation and visual inspection; The other is to measure it with a ruler, mark the length and compare it. Learn the right way from it.

Verb (abbreviation of verb) class summary

What did you learn in this lesson? What else do you know?

I. Introduction to the conversation

Before introducing these two new friends, let's recall our old friends. In the previous research, we already know the unit of length (meters, centimeters). Please indicate by gesture how long 1 m and 1 cm are respectively. What is the relationship between them? 1 m = 100 cm

2. Explore new knowledge

(1) Understanding millimeters

1. After seeing our math book, can you estimate its length and width respectively? (Students say) Are they right? Let's verify it. Two students at the same table cooperated and measured its length and width with a ruler. And write it down, think about it first, which unit should I use?

Number of students, teacher's guidance.

Report the measurement results.

2. When the measured length is not the whole centimeter, we can't accurately express the length and width of the textbook. So the teacher wants to introduce a new friend in the family of length units-millimeter.

The teacher shows the ruler and displays it on the physical projector, enlarging it by 0- 1.

Teacher: Observe the scale line between 0- 1 What do you see?

These tick marks divide the scale of 1cm into cells of equal size, and the length of a cell is1mm.

Question: How long are two cells? What about the five squares? How many cells are there in 7 mm?

Teacher: Let's take out the ruler, find 1 cm, point it with a pencil and count how many squares there are in 1 cm. (10), each 1 cell is 1 mm, so how many millimeters is 1 cm?

Students communicate after hands-on operation.

Teacher's blackboard: 1cm = 10mm

4. What do you think of millimeters? Take out a penny in your bag, have a look and feel it. The thickness of this penny coin is about 1 mm. What other lengths have you seen in your life are1mm? (thickness of calling card, 10 thickness of paper) Tell me, what items in life are usually measured in millimeters?

5. Do it. The third side of the textbook. Collective revision.

6. Take out a one-dollar coin and measure its thickness with a ruler.

Some students found that the thickness of 1 yuan coin is not exactly 2mm, but 2mm less. If we want to get more accurate results for objects that are not full millimeters, will you have new wishes?

Guide: In fact, there are units of length smaller than millimeters, such as microns and nanometers. Students can consult reference books after class, or ask others for advice, or go online to find more knowledge.

(2) Understand decimeter

1.( 1) Computer demonstration: The beverage company recently launched a new type of boxed beverage (photo). The height of the beverage is 8 cm, and the beverage is equipped with a straw. Please guess how long this straw is.

Students guess and communicate. Teacher's summary: the length of straw must be greater than 8 cm.

Teacher: Children really use their brains. Now this straw is on your desk. Do you want to measure it? How long is it?

The students began to measure, and the teacher patrolled.

⑶ Students report the results: The length of straw is exactly 10 cm.

Teacher: The length of 10 cm can also be expressed by a new length unit. This is the new friend of the second family of length units to be introduced to you today-decimeter. 1 decimeter = 10/0cm

2. Put your finger on the ruler. How long is 1 decimeter? Put down the ruler and raise your hand. Compare it with drawing 1 decimeter.

3. What else have you seen in your life that is about one centimeter in length? So what can be measured in decimeters?

Can we measure the length of our table? You can estimate it first, or you can draw it by hand. What is the length of the desktop? If the teacher's meter ruler is good, but the ruler in your hand is short, how should you measure it? (Each paragraph 18cm, look at a * * *, how many paragraphs are there. This is more difficult to calculate. Is there a simpler calculation method? Every 10 cm, that is, 1 decimeter is a section, so two people at the same table measure it together.

Students cooperate to complete and report.

5. How long is the tape on my blackboard now? (1 decimeter)

Stick another 2 cents. How's this? (2 decimetres)

Stick it for another 3 minutes. How long is this? (3 decimetres)

Put another 4 cents. How long is this? (4 decimetres)

How long are they? (10 decimeter) means 1 meter.

/kloc-How many centimeters is 0/0 decimeter? (100 cm)

100 cm, which is how many meters? (1 m)

If the length of this tape measure is 10 decimeter, it should be as long as this meter scale, right?

Metre scale verification. Is it long above? (10 decimeter) bottom length (1 meter)

What does that rice have to do with decimeter?

1 m = 10 decimeter (blackboard writing)

Three. Summarize.

1. Together with the two new units we learned today, we know the names of several length units. Then can you arrange them? (meter, decimeter, centimeter, millimeter from big to small; Millimeter, centimeter, decimeter, meter from small to large. )

Fourth, consolidate the exercises.

1. Xiaoming's diary.

Dialogue: After learning mathematics knowledge, you should use what you have learned to solve practical problems in daily life. Xiao Ming of Class 1 (3) wrote a diary and recorded his mother's birthday. Do you want to read it?

Show:

It was sunny on March 7, 2005.

This morning, I got out of a 2-meter-long bed and went to the bathroom. I brushed my teeth with a 1 meter toothbrush, washed my face in a hurry and had breakfast. The school is not far from my home, about 500 mm On the way to school, I saw a 2 cm tall tree broken by the wind, so I quickly found a rope with a length of 1 cm to tie the young tree. I ran to the school and found the teacher already lecturing in the classroom. I quickly took out a pen with a length of 1mm and a notebook with a thickness of 4m from my schoolbag and began to take notes.

Students may laugh. Ask the students to tell the reasons for their laughter and help correct math diary. Ask the students to compare the actual lengths of these objects and help them choose the appropriate length unit. )

Understanding of decimeter and millimeter in blackboard writing design

Zhu from Jingbei Primary School in Xixiang

Teaching material analysis:

This lesson is taught on the basis that students have learned the length units of meters and centimeters and mastered the method of measuring objects. The arrangement of teaching materials has the following intentions: 1. Through the activities of estimation and measurement, students will realize the necessity of introducing decimeter and millimeter length units;

2. Learn new length units in actual measurement activities;

3. Further cultivate students' estimation consciousness and develop students' spatial concept.

Instructional design concept:

Combined with my own research topic "Study on Giving Full Play to the Role of Evaluation to Promote Students' Autonomous Learning Strategies", I designed this course into three levels: 1, technical evaluation and interest introduction. Teachers and students talk for a few minutes at the beginning of class, and skillfully use evaluation to narrow the emotional distance between teachers and students, so that students can be prepared to enter the learning state quickly; 2. Use evaluation skillfully to discover new knowledge. This consideration stems from the students' existing knowledge of learning this lesson. What teachers should do next is to think about how to mobilize students' internal driving force and promote students' active participation in learning activities. My strategy is to provide students with opportunities for autonomous learning through activity design, and then adopt diversified evaluation methods to encourage students to actively participate in learning activities, give full play to the role of evaluation in classroom teaching, and promote students' autonomous learning. 3, interactive evaluation, consolidate and expand. The active application of knowledge stems from students' interest in practice and teachers' and students' evaluation of its performance. I try to think about the design of practice from these two aspects.

Teaching objectives:

1. By measuring the length of the pencil, we can know how long 1 decimeter and 1 millimeter are, and develop the space concept and hands-on operation ability.

2. Understand the relationship among meter, decimeter, centimeter and millimeter through actual measurement.

3. Cultivate students' estimation ability through activities such as estimation and measurement.

4. Let students experience the fun of learning in mathematics learning activities and get a better emotional experience.

Teaching emphases and difficulties:

1, the length unit is known in actual measurement activities.

2. Cultivate students' awareness of estimation.

Teaching process:

First, the clever use of evaluation, to introduce interest

Teacher plays the animation: Guess what we learned today? (Clever evaluation)

Teacher: In the wonderful mathematics kingdom, there is such a family length unit, and our life can hardly be separated from them. Son, who have you met in this family?

As the teacher spoke, he showed cartoon cards marked with meters, centimeters, decimeters and millimeters in turn to reveal the topic.

Teacher: What do you want to know about decimeter and millimeter?

Second, the clever use of evaluation to explore new knowledge

(A) create a situation about pencils

Yesterday, when the teacher was on duty, it happened that two children in grade one were arguing and went over to ask. It turned out that they were arguing about throwing pencils: one said that these pencils were too short to use and wanted to throw them in the trash can; Another said that although these pencils are a little short, they can still be used. I brought all these pencils. How long is it not suitable for use? I want to ask my little brothers and sisters to help them, okay?

(2) Activity 1: Understanding decimeter

1. Estimation and measurement.

(1) The teacher took out a pencil. Next, the teacher will test your eyesight and estimate: How long is this pencil?

How long is this pencil? What should I do? (born on the stage, comment: how did he measure it? )

(3) Courseware demonstration: Which measurement method is correct?

(4) Estimate and measure the length of the straw.

Is the straw as long as this pencil? How long is it? Do you know what 10 cm can be called? Can you express it in letters? (Let the students speak first, and the teacher will evaluate)

2. Understand the relationship between decimeter and centimeter

Can you find 1 decimeter from the ruler? From where to where is 1 decimeter. How do you know this is 1 decimeter? Tell it to your deskmate.

Teacher's comment: What a group of clever children! They all found 1 0cm from the ruler, which means1decimeter. 1 decimeter How many 1 cm are there? (blackboard writing: 1 decimeter =10cm1DM =10cm)

3. Experience 1 decimeter and the length of decimeter.

(1) one-to-one

Draw 1 decimeter on the ruler with your small hand and hold it up for everyone to see. What did you find?

(2) Say it out

Think about it. In your life, which objects are about 1 decimeter in length?

Teacher's comment: The children really have a heart for life and found so many things 1 decimeter long.

(3) estimation

Estimate the real thing first, and then estimate the ribbon (in the form of a game)

Guess: How many decimetres is this meter ruler?

4. Perceive the relationship between meter and decimeter.

(1) Take out the meter ruler and observe it carefully: 1 How many decimeters are there in the meter?

(2) Group communication: What did you find?

Mutual evaluation: who can observe best, who finds the most remarkable. (blackboard writing: 1 m = 10 decimeter 1m= 10dm)

Step 5 solve the problem

Teacher: Children, do you think this pencil 1 decimeter long can still be used?

The teacher took out another short pencil: Is this one still usable? Let a student try: How do you feel?

How long is it? Make an estimate first.

(3) Activity 2: Know Millimeter.

1. Measure.

Measure it. Look, how long is it?

Please watch carefully. Is it 5 cm? It's over 5 cm. How many squares are there on this ruler? Do you know how long the cell 1 is? How many small squares are there in 1 cm?

Courseware demonstration

Draw a conclusion:1cm =10 mm.

2. compare it.

How long is 1 mm? Please make a gesture to the ruler.

Look, your little hands are almost glued together. What do you think of 1 mm? 1 cm is so much, and 1 mm is much shorter than 1 cm.

Look for it.

What objects in life are about 1mm long? (Team work completed) Roll call report.

Guess: How many millimeters are five coins stacked together? How many playing cards add up to about 1 mm?

Talk about it

Courseware playback: measuring the length of paper clips and pins

(4) Summary

I didn't expect that when we were helping the first-grade children solve the pencil problem just now, we met two new members of the family of length units-decimeter and millimeter. What do you know about them?

Third, interactive evaluation, consolidate and expand.

1. Competition

Children, we used to be friends with Mimi, but today we have made two new friends-decimeter and millimeter. Let's play the game of change, change, change, shall we?

The teacher said the length, the children think about it, change it and see who becomes better and faster:

(1m- 1 decimeter-1 cm-1 mm-10 cm-10 decimeter-)

Comment: Who has the fastest response?