1. Let the students know the length unit centimeter and establish the concept of 1 centimeter.

2. Learn how to measure the length of an object with a scale (limit the number of whole centimeters).

3. Cultivate students' observation and hands-on operation ability.

Teaching focus

Master the actual length of 1 cm and learn how to measure objects with a ruler.

Teaching difficulties

Establish the concept of length of 1 cm.

Learning tools and teaching AIDS

Slides, notes, sticks, rulers, nails, thumbtacks, etc.

teaching process

View import

1. Ask students to compare their desks with pencils, scraps of paper and nails prepared before class, and then report the length of each desk according to their different measuring tools. (The answers are varied: 4 feet long and 8 pieces of paper ...)

2. Teacher talk: The students are right, but why are the results different? Because we use different things to measure the table.

3. Import: In order to obtain consistent results, we need a unified measurement tool. Does anyone know what a tool for measuring length is? (Ruler) Just now, a classmate measured the length of the desk with a ruler, but I don't know what unit to use and how long the desk is. Today we are going to learn the units and measurement methods used in case of shortage. (blackboard writing: knowing centimeters, measuring centimeters)

Teacher: When we want to measure the length of a relatively short object, we usually use "centimeter" as the unit of measurement.

Second, new funding.

1. Know the length unit "cm"

Teacher: Please take out your ruler and find the scale "0". From scale 0 to 1, the middle length is 1 cm.

Teacher: Take a good look. How long is 1 cm?

Teacher: Close your eyes and think about how long 1 cm is?

Q: Let's find out what is the closest length to 1 cm (the diameter of buttons, the width of nails, the width of teeth, the thickness of rubber ...) among the things you brought and the things around you.

Look at the ruler. Where is 2 cm long? Encourage students to say different answers, such as: from scale 0 to scale 2 is 2 cm; From scale 1 to scale 3 is 2 cm; From level 5 to level 7 is 2 cm ...)

Look at the ruler. Where is it 3 cm long? 5 cm long from where to where? (report)

Q: What do you find by looking for these different lengths on the ruler?

(1. The scale is from 0 to several centimeters; 2. Subtract the big scale from the small scale to get a few centimeters; 3. Just a few centimeters. How many 1 cm are there in these centimeters? )

2. Learn to use centimeters

Try to measure the same learning tool (an 8 cm long stick)

Teacher: Every student has a stick. Would you please try to measure the length of this stick with a ruler?

Q: What is the result of the measurement? Tell me how you measured it.

Compare the correct method and the wrong method (demonstrate the two methods with physical projection), so that students can identify the correct method.

Summary: When measuring an object, aim the ruler "0" at one end of the object and then look at the other end of the object. The length of this object is several centimeters.

Student activities: First, choose a learning tool you brought and show it to the students. It is estimated that its length is several centimeters. Then actually measure the length of the selected object to see if it is equal to the estimated value.

3. Teacher: What have you learned through your study?

Third, consolidate the practice.

1. Basic exercises

Take out a piece of string, measure 3 cm and 5 cm respectively, and compare it with the students next to you to see what you find.

Step 2 develop exercises

Q: If the scales in the first few squares of a child's ruler are unclear (showing the picture "worn ruler"), is there any way to measure the exact length of an object with this worn ruler?

Fourth, inductive questioning.

What did you get from this lesson? Is there a problem?

Verb (abbreviation for verb) assigns homework.

1. After you go home, measure the length of some objects you like in centimeters.

2. Investigate after class to find out which objects in life are measured in centimeters.

blackboard-writing design

Know centimeters in centimeters.

centimetre

When we want to measure the length of a relatively short object, we usually measure it in centimeters.

Measurement method: aim the scale of ruler "0" at one end of the object, and the other end of the object faces the scale, so that the length of the object is several centimeters.

Comments on teaching plans:

When importing, let students report the length of each person's desk with different measuring tools, and then naturally lead out the math teaching plan of measuring unit and measuring method through a question of "Why the results are different"-knowing centimeters with centimeters, and the math teaching plan of primary school "Mathematics Teaching Plan-Knowing centimeters with centimeters".

When teaching to know centimeters, let students use their imagination first, and then feel the length of 1 centimeter through real objects, so as to realize the cognitive process from abstract to concrete.

When measuring the length of the stick, the teacher lets the students learn actively and explore methods, which is conducive to mobilizing the enthusiasm of the students; Then the teacher measures the students with standardized movements and standard measurement methods, so that students can have an epiphany in comparison with their own operations, so as to master the essentials of quantity; Finally, through personal practice, the mastery of knowledge and skills has experienced a gradual process from shallow to deep, from the outside to the inside.

Mathematics Teaching Plan-Understanding Centimeters with Centimeters