How to write the teaching plan for comparing the decimal size of mathematics in grade four?

First of all, doubt arouses interest.

1. Demonstrate the animation "Decimal Size Comparison".

The teacher asked: which of the two children is taller and heavier? what do you think?

How to compare the sizes of decimals? (blackboard writing topic)

2. Make a bold guess:

Give an example of how integers compare sizes. (When the integer digits are the same, compare them from the high position; When the number of digits is different, the more digits, the greater the number)

3. Compare the sizes of the following integers:

Teacher's question: According to your knowledge and experience, and your understanding of decimals, can you try to talk about how decimals compare with sizes?

Second, try to explore.

1. Teacher's question: According to your guess, compare the sizes of the following two groups of decimals with your method, and talk about your thoughts. (1) 9.7 yuan and 5.9 yuan (2) 6.79m and 6.85m

2. Student report:

(1)9.7 yuan is the 7th corner of 9 yuan, while 5.9 yuan is the 9th corner of 5 yuan. The 7th corner of 9 yuan is larger than the 9th corner of 5 yuan, so 9.7 yuan > 5.9 yuan;

(2)6.79 meters is 6 meters, 7 decimeters and 9 centimeters, and 6.85 meters is 6 meters, 8 decimeters and 5 centimeters.

Because 6.79 meters is less than 6.85 meters and 6.70 meters is less than 9 centimeters.

3. The teacher asked: How do these two groups of decimals compare in size?

When comparing, we start with the integer part. If the integer part is large, the decimal part is large. If the integer parts are the same, it is ten digits. If the integer part is large, the number is large. )

4. What do you find by comparing the sizes of the following decimals? (i.e. Examples 5 and 6)

2.35 yuan and 2.4 1 yuan 0.07 meters and 0.059 meters.

Student report:

(1)2.35 yuan is 35 points in 2 yuan and 2.4 1 yuan is 1 minute in 2 yuan, so: 2.35 yuan < 2.4 1 yuan.

(2)0.07 m means 7 0.0 1 m, and 5 of 0.059 m are 0.0 1 m, so 0.07 m > 0.059 m (which can guide students to find out the corresponding length verification and comparison results with a ruler. )

(If the integer parts are the same, compare the decimals, and the decimals are the same, and then compare the percentile. The bigger the number in the percentile, the bigger the number. )

5. The teacher summed up how to compare the sizes of decimals:

Look at the integer part first, and the number with a large integer part will be large; If the integer parts are the same, the decimal places with large numbers will be large; If the deciles are the same, compare the percentiles and so on.

6. Teacher: What's the difference between our method of comparing decimal sizes and your initial guess?

Just try it.

1. Replay the animation "Comparison of Decimal Size" to help two students grow taller and weigh more than their parents.

2. In a group of two students, one will say two decimals at will, and the other will compare the sizes of decimals. It is required that the number of decimal places should not exceed four.

Fourth, consolidate practice.

1. Compare the sizes of the following decimals.

7.9○8.2 0.5 1○0.509 1.374○ 1.3

5.7○5.8 0.6○0.60 1.23○ 1.32

2. Arrange the following decimals from small to large.

0.8 0.807 0.078 0.87 0.78 0.087

Focus on guiding students to talk about comparative law.

3. Judges:

( 1)6.809 & gt； 6.799()(2)5. 1 & gt； 5. 1002( )

(3)38.748 & lt； 38.75()(4)0.009 & gt； 0.0 10( )

Verb (abbreviation of verb) class summary.

Through the study of this class, students have mastered new methods, hoping to use what they have learned to solve some practical problems in life.