Primary school mathematics teaching plan "Understanding decimeter" 1 Teaching goal (1) Pupils know decimeter, centimeter and millimeter, know the actual length of these units, and establish the corresponding length concept. The speed of progress between them.
(2) Master the method of measuring the length of an object with a ruler, and use a ruler to measure the length of a shorter object.
(3) By means of intuitive demonstration, operation, observation and generalization, students' initial logical thinking ability and invention and creation ability are cultivated.
The focus of teaching is to let students establish specific concepts of decimeter, centimeter and millimeter, which is also a difficult point.
Talk before class
1. Dialogue (shows ruler): Students, do you know what this is? (Ruler) Yes, this is a ruler that people can't live without. Do you know why people invented rulers?
Transition: In order to know the length of an object accurately, people invented a ruler. What does the ruler tell us about the length of the object? Now let's get to know the ruler.
2. Students observe their rulers and discuss and communicate in groups of four. The whole class is packed.
(1) What did the student observe on the ruler? There are long and short lines, numbers, big squares and small squares on the ruler. )
Guide and write on the blackboard: these long and short lines on the ruler have a name called tick marks. (blackboard writing scale line)
(2) Find out: How are the numbers and lines arranged?
Blackboard Guide: The long tick marks of the number 0 pairs are named as 0 tick marks. Do you know what this 0 means? (The 0 here is not nothing, but the starting point.) Can you also learn to name the long tick mark with the number 1? (1 tick mark), there are five pairs of long tick marks called ()?
(3) Description: What is the distance between adjacent tick marks, which we call the length of the cell? We call the distance between adjacent long tick marks a large grid. Count your ruler with the () grid. There are () small cells in a big cell.
3. Summary: The ruler tells us the length through these scales and numbers.
Primary school mathematics teaching plan "decimeter understanding" 2 teaching objectives
Knowledge and skills
1. Understand decimeter and establish the concept of length of 1 decimeter.
Knowing the relationship between decimeter and centimeter, meter and millimeter, we can simply convert length units.
Process and method
1. Go through the process of logical reasoning to improve students' reasoning ability.
2. Go through the process of combing the relationship between the four length units to deepen the understanding of the decimal relationship between the length units.
Emotions, attitudes and values
1. Feel the practical significance of decimeter in the process of learning, and realize that mathematics comes from life and is applied to life.
2. Experience the rigor and scientificity of mathematics in the process of hands-on operation.
Important and difficult
Key point: If you know decimeter, you can use decimeter to measure the length of an object, knowing decimeter = 1 cm and decimeter = 1 cm.
Difficulties: Establish the concept of length of 1 decimeter.
Preparation before class
Teacher's preparation: PPT courseware, ruler, meter ruler, 10 cm long note, class activity card.
Students prepare: ruler, meter ruler, 10 cm long note, pencil, exercise book.
teaching process
Section 1 review old knowledge and pave the way for new lessons.
1. Say the learned unit of length. (m, cm, mm)
2. What is the maximum length unit you have learned? What is the smallest unit of length? (mm)
3. Ask students to draw the approximate lengths of 1m, 1cm and 1mm by hand.
In the actual measurement, we can choose the appropriate length unit according to the specific situation.
Homework guidance: During the homework in this section, students should pay attention to the mastery of the units of length they have learned, clear up the existing problems in time, avoid the obstacles of learning new knowledge, and pave the way for systematically sorting out the relationship between units of length.
Plate 2 explores the operation and acquires new knowledge.
Activity 1 Explore the introduction and reveal the topic.
(Show the class activity card, see page 66 of this book)
1. Guide the students to discuss which length unit is suitable for measuring the length of the table.
Students report after discussion: choose centimeters, because the length of the desk is not enough 1 meter, and the millimeter is relatively small. If it is measured in millimeters, the measured number will be larger and the measurement process will be more troublesome.
2. Students use learning tools to measure in groups.
3. Report the measurement method.
Method 1: Take the maximum scale of a ruler as a section and measure it continuously, and the length of the table can be obtained as 97 cm.
Method 2: Take a piece of paper with a length of 10 cm as a section and measure it continuously. A * * has nine pieces 10 cm. Measure the rest with a ruler and add 7 cm. It can be concluded that the length of the desk is 97 cm.
4. Compare measurement methods.
Guide the students to discuss which method is better and why.
Student report: Method 2 is better. Because it is measured on the section of 10 cm, it is easy to remember and calculate, and it is not easy to make mistakes. In the first method, the maximum scale of the ruler is 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, which is easy to make mistakes in calculation.
5. Secret topic: The 10 cm we just said is 1 decimeter. In this lesson, we will learn decimeter together. (blackboard title: understanding decimeter)
Activity 2 Observe the operation and learn 1 decimeter = 1 0cm,1meter =1decimeter.
1. Teaching 1 decimeter =10cm.
Take a meter ruler and point out the length of 1 decimeter.
(1) Ask the students to count how much of 1 decimeter is 1 cm, and make it clear that 10/cm is 1 cm, that is,1decimeter. (blackboard writing: 1 decimeter =10cm)
(2) Ask students to gesture 1 decimeter, and then think: How to express the length of the desk in decimeter and centimeter?
(3) Discuss in groups how to express the length of desks in decimeters, and then report. The desk is 97 cm long, and 90 cm is nine 10 cm, which is 9 decimeters. If you add 7 cm, it is 9 decimeters and 7 cm long.
2. Teaching 1 m = 10 decimeter.
(1) Guide students to explore the relationship between decimeter and meter in groups, and then report with the help of meter ruler or calculation.
Team 1 Our team observed the meter ruler and learned that 1 decimeter = 10 cm, so we took 10 cm as the length unit, and a * * segment with 10 was 1 m, that is1m.
The second group is derived by our group from the relationship between meter and centimeter, decimeter and centimeter. 1 m = 100 cm, where 10 is 10 cm and 10 is 10 cm. (blackboard writing: 1 m = 10 decimeter)
(2) Ask students to arrange the length units they have learned in the order from long to short. (meter > decimeter > centimeter > millimeter)
Activity 3 Observe the real thing and establish the concept of 1 decimeter.
1. Observe and compare, and establish the concept of length of 1 decimeter.
(1) Observe the length of 1 decimeter on the ruler, understand the decimal relationship between length units, and draw 1 decimeter by hand. (repeated twice)
(2) Let's have a small competition between deskmates to see which classmate can win.
Please indicate 1 decimeter with the gesture of the classmate sitting on the south side, and measure it with the ruler of the classmate sitting on the north side. Change roles and test again. (Mutual measurement at the same table) Which is closer to the length of you and the representative at the same table 1 decimeter? I hope you can help your deskmate express 1 decimeter accurately with gestures. (student operation)
2. Estimate, draw and experience the expression of 1 decimeter length.
(1) Estimate the position where the middle finger tip reaches the hand, which is about 1 decimeter? Ask your deskmate to measure you and see if you can estimate it correctly. (deskmate activity)
(2) Draw a picture.
We already know the approximate length of 1 decimeter just now. Please take out your pencils, rulers and exercise books, and draw 1 decimeter on the exercise books with the uncalibrated side of the ruler. After painting, measure it with a ruler and see if you can draw it correctly.
Please draw a line segment with a length of 2 meters and 3 meters respectively, and then measure it with a meter ruler to see if you can draw it correctly.
(3) Think about it. What objects around us are about 1 decimeter in length? Which objects are suitable for measuring their length in decimeters? (Students report after thinking)
3. Systematically sort out and understand the decimal relationship between length units.
(1) conversion between meters, decimeters, centimeters and millimeters.
Ask the students to recall the length units they already know. What is the progress rate between them?
② Courseware shows 23 pages of teaching materials. Guide students to solve problems with what they have just learned.
2 cm = () mm
80 cm = () decimeter
Think: 1 cm is 1 0mm, think:10cm is1decimeter,
2 cm is () 10 mm. There is () 10 cm in 80 cm.
Ask the students to say why they fill in this form and what they think.
(2) Feedback exercise: Complete the "doing" on page 23 of the textbook.
(3) Ask students to sort out the relationship between millimeters, centimeters, decimeters and meters with charts.
Operations Guide: The difficulty of this section lies in the simple conversion between length units. Therefore, it is necessary to establish the' representation' of four length units in operation, so that students can establish the concept of 1 decimeter in activities such as estimation, comparison and drawing, and systematically sort out the decimal relationship between length units, thus breaking through the difficulties of this lesson.
Plate 3 Consolidation exercise, expansion and extension
1. Is the unit used correctly in the following questions?
(1) The length of the pen is 14 decimeter. ( )
(2) The bed is 2 cm long. ( )
(3) flagpole height 12m. ( )
(4) The width of the writing desk is 100mm. ( )
(5) The exercise book is 2 decimetres long. ( )
2. Complete the textbook with 24 pages and 4 questions.
Master Wang sawed a 4-meter-long wood into 5-meter-long pieces. How many segments can he saw? (The loss of wood is not counted)
(Students finish independently first, and then revise collectively)
Section 4 Class Summary and Homework.
1. class summary.
(1) What did you learn today?
(2) How did you learn it?
(3) Do you have any questions?
Health: I learned 1 decimeter = 1 0cm,1m =1decimeter; I learned it by observing instruments and rulers. My question is, is it appropriate to measure the length of all objects in decimeters?
2. Assign homework.
(1) The textbook has 24 pages and 3 questions.
(2) Questions 6 and 7 on page 25 of the textbook.
blackboard-writing design
Understanding of decimeter
1 decimeter =10cm
1 m = 10 decimeter
Teaching reflection
The teaching content of this course is boring and difficult to understand, but it is also a practical course. To this end, I designed a series of students' hands-on practice activities, aiming at increasing students' understanding and application of decimeter through their own hands-on practice.
When students measure the length of desks, they find it troublesome to measure in centimeters. First, the data is relatively large. Second, the students' ruler is relatively short, which needs to be measured many times, and the error is large. At this time, some students said that decimeter was used as the unit of measurement and decimeter was naturally introduced. In the actual operation process, students found the relationship among decimeter, centimeter and meter, and established the concept of length of 1 decimeter.
To know how long decimeter 1 is, it is not enough just to listen to lectures. It is impossible to establish the representation of length units overnight. Teachers need to carefully design effective links, so that students can use their brains, move their mouths and do things, so that students can feel constantly in actual operation and gradually strengthen their understanding of decimeter. The concept of establishing the length of 1 decimeter with a ruler is often not firm. If you leave the ruler or every once in a while, your first impression will be forgotten. Therefore, I think students should get out of their seats, look for 1 decimeter and tell which objects are about 1 decimeter in length. First, feedback, check whether the students' first perception of the ruler is effective. Second, let students remember the length of 1 decimeter with the help of the familiar objects they find. Later, when recalling the length of 1 decimeter or judging the length of other objects, they can use the length of familiar objects as a reference.
In the following teaching activities, I ask students to make bold estimates and combine the estimates with the actual measurements. Let the deskmate cooperate when studying: (1) Let a student stretch out his thumb and forefinger and draw 1 decimeter. Now the drawing is one foot long, and one foot long is about 1 decimeter. Draw a picture for your deskmate. (2) One person draws 1 decimeter, and the other person measures it with a ruler to see if the estimation is correct. (3) Take out the paper, estimate the length of 1 decimeter, cut it at about 1 decimeter, and measure it together to see who estimates it most accurately. By drawing and hand-drawing on a ruler and estimating the length of 1 decimeter on a piece of paper, the difficulty of measurement is gradually increased, so that students can gradually deepen their understanding of decimeter and cultivate their ability and consciousness of estimation. Although this classmate's estimate of 1 decimeter is not very accurate, it should be encouraged as long as it is close. Let students observe with their eyes, communicate with their mouths, operate with their hands and think with their brains, and feel that mathematics knowledge comes from life, and provide them with a stage for autonomous learning, which is conducive to cultivating students' initiative in learning.
I deeply feel that teachers should be able to let go, dare to let go, and truly believe that students have the ability to feel, discover and innovate through their own efforts. In this class, students learned all the knowledge points through independent inquiry and cooperation, which was better than expected. I think students should be given their own space, so that they have the opportunity to discover and master knowledge by themselves.
Primary school mathematics teaching plan "decimeter understanding" 3 Teaching purpose:
1, cultivate students' good habit of careful observation.
2. Understand the length units of millimeters and decimeters, and initially establish the length concepts of 1mm and 1mm,1cm =10 mm; 1 m = 10 decimeter.
3. Cultivate students' practical ability.
Key points: Know the length units of millimeters and decimeters, and initially establish 1 mm and 65438+ decimeters. The concept of length is known as1cm =10 mm; 1 m = 10 decimeter.
Difficulties: How to measure the length of an object correctly in millimeters and decimeters?
Guan: the method of combining intuitive demonstration with hands-on practice is adopted.
Teaching tools: courseware, meter ruler, student ruler, string, various small objects, etc.
Teaching process:
First of all, set questions, stimulate interest and introduce new lessons.
Teacher: There is a short line segment on each set of paper. Can you measure its length accurately? Give it a try! 1, student group activities. 2. Report: The length of the small line segment cannot be measured.
Teacher: How can we calculate the length of a short segment?
Health: If you know how long a cell is, you can calculate it.
Teacher: How do you want to solve this problem?
Health: Reading.
Teacher: Please open page 60 of the book and learn by yourself 1.
Comments: Only when you have doubts can you think. By measuring the line segment, teachers deliberately set questions for students and stimulate students' interest in inquiry. Every student wants to solve the problem through his own efforts, and his enthusiasm is very high!
Second, cooperate and explore to form a law.
Teacher: Who can tell the teacher how long a cell is?
Health: a small cell 1mm long.
Teacher: Can you explain in detail how it is stipulated?
Health: 1 cm, and each cell in the middle is1mm.
Teacher: Let's watch the big screen.
Teacher: This is an enlarged 1 cm. Let's count how many cells there are. The length of this unit is 1 mm. How many millimeters are two cells? How many millimeters are five cells? 1cm How many 1mm are there? So how many millimeters is 1 cm?
Teacher: Measure, how thick is a penny?
Health:1mm.
Teacher: Use gestures to indicate the length 1mm?
Measure the length or thickness of small objects around you in groups, with division of labor, records and clear division of labor.
Students work in groups.
Students report in groups.
Teacher: When we measure small objects or ask us to measure accurately, we should use millimeters as the unit. When we measure long objects, we should use a unit of length much larger than millimeters. You want to know what it is? Open page 6 1 of the book and learn Example 2 by yourself.
(1) Students teach themselves. (2) Student report: the length of 10 cm is 1 decimeter.
Teacher: How many centimeters is 1 decimeter? How many decimetres is 1 meter?
Continue to work in groups to see which objects can be measured in decimeters. (1) Student group activities. (2) Students report in groups.
Gesture length is 1 decimeter. Measure a 3-meter-long rope for everyone to see.
Think about it. What did we learn in this class? What units of length have we learned so far?
(The big screen shows the learned length unit)
Teacher: What is the forward speed between every two adjacent length units? Can you arrange them from small to large? Is there anything you don't understand about this course? Will the teacher test you with a question?
Comments: In the new teaching process, I mainly adopt the following methods: independent method, cooperative method, inquiry method and practical operation method. On the basis of students' self-study, I provide opportunities for students to cooperate and explore, and help them to establish the length concepts of 1mm and1mm. For example, measuring the length or thickness of objects around you with millimeters and decimeters not only cultivates students' cooperative spirit, but also cultivates students' practical ability, fully connects with students' real life, and makes students feel personally about what they have learned, with high enthusiasm and good learning effect.
Third, consolidate the practice.
1, fill in the appropriate length unit.
This crayon is 6 () long. (2) Skipping rope is 2 () long.
This table is 7 () high. The length of chalk is 75 ().
(5) The length of the pin is 34 (). (6) Xiaohong is 120 ().
2. Judges
(1) nickname height 134 meters. () (2) The length of the rope is 15 decimeter. ( )
(3) The thickness of a piece of rubber is1m. () (4) 10 decimeter = 1 cm. ( )
3. Children's songs
There are many units of length, such as meters, decimeters, centimeters and millimeters.
Some are long, some are short, and some are neither long nor short.
1 m = 10 decimeter, 1 decimeter = 1 0cm,1cm =10mm.
Be sure to remember it firmly and use it flexibly.
Comments: In the consolidation exercise stage, some forms that students like are adopted, such as selection, judgment and nursery rhymes. It not only tests the students' knowledge of this lesson, gets feedback information in time, but also mobilizes the students' enthusiasm, so that students can play middle school and learn through fun.