Examples and "Try it" on page 6 1 and "Think about it and do it" on page 62.

Teaching objectives:

1, so that students can experience the exploration process of finding the difference between two numbers, and understand that how much one number is more than another number is calculated by subtraction, thus solving other simple practical problems in daily life.

2. Make students learn to communicate with others in the process of solving practical problems, and cultivate their interest in learning mathematics and their awareness of applying mathematics.

Teaching process:

First, review and pave the way

1, show me the oral calculation (the courseware is complacent)

2. Dialogue: We have learned to compare, such as size, length, weight and amount.

① Specific size

Show a textbook and an exercise book. Question: Comparing textbooks and exercise books, which cover is bigger? How do you compare?

② Specific length

Show two pencils and ask: which one is longer and which one is shorter?

(3) What is the ratio?

Display projection: contrast

④ It is pointed out that comparison is a common method in our daily life. Today, in this class, we will learn how to compare many results by calculation.

Second, the method of inquiry

1. Show me your parachute. How much do you compare?

Please look at the big screen and see what is floating in the sky. (Health: Parachute)

Yes, beautiful parachutes are falling in the sky, including red parachutes and yellow parachutes Who has more yellow parachutes or red parachutes? How many are there? Please observe carefully.

The teacher now uses the red circle to represent the red parachute and the yellow circle to represent the yellow parachute.

Health: There are 1 1 red umbrellas and 7 pholiota adiposa.

Teacher: Actually, the red umbrella can be divided into two parts. One part is seven times that of pholiota adiposa, and the other part is more than seven times that of pholiota adiposa. Look, this is where there are more red umbrellas than pholiota adiposa. Q: How many (four)?

So how do we work out the formula now? Students answer, the teacher's blackboard 1 1-7=4 (sheets)

In the activity class, Xiaoming and Xiaohong are playing a game of catching snowflakes.

Let the children say what Xiaoming said, and then say what Xiaohong said. Do you know which kind of snowflake catches more? How much more?

② Show the courseware, and arrange the red snowflakes and blue snowflakes neatly and align them one by one. Who can tell me which two parts the red snowflake is divided into?

Some have as many red snowflakes as blue snowflakes, while others have more than blue snowflakes.

Formula: 13-8=5 (unit)

Do you know how much less blue snowflakes are than red snowflakes? (display projection)

Health: The red snowflake is divided into two parts, one is as much as the blue snowflake, and the other is more than the blue snowflake.

Hint: What else can I choose?

Health: It can also be said that there are five fewer blue snowflakes than red snowflakes.

Display formula: 13-8=5 (pieces)

3. Show the topic: Find how much more (how much less) one number is than the other.

This is what we are learning today: read the summary together: to find how much one number is more than another or how much one number is less than another, in fact, to find the difference between two numbers, which is calculated by listing the same formula by subtraction.

Third, consolidate

1. The teacher "Try" in the book talked about this problem. How many boys are less than girls?

The first time I reread Shao, the second time I reread People, and asked: Why?

Can you calculate vertically?

2. "Thinking in groups" in the book

One day, the bear and the monkey helped the hen pick corn in the field. The little monkey picked 53 grains of corn and the little bear picked 30 grains of corn. Do you know how much more corn the monkey picked than the bear?

(student column calculation)

② Do the second question "Think about it and do it"

Guide the students to observe their intentions and ask: which two books are drawn in the picture? How many books are there in the math story? How many fairy tales are there? What are the questions that must be asked?

Let the students answer in columns.

③ Complete the third and fourth questions of "Thinking and Doing" independently.

Fourth, the class summarizes.

Today, we learned the practical question "How much is one number more than another?". What methods should we use to solve such a problem?

Reflection:

The new curriculum standard requires that teaching should fully consider the characteristics of students' physical and mental development, combine students' life experience and existing knowledge, and design interesting and meaningful activities, so that students have more opportunities to learn and understand mathematics from familiar things around them. How much is one number more than the other?

In this class, I try my best to provide students with a relaxed learning environment, reduce their psychological pressure and cultivate the quality of getting along with others. Let students observe and analyze as much as possible, let students think positively, guess boldly and explore actively. Cultivate students' mathematical communication ability, learn to listen and think in communication, and promote mathematical thinking activities.

According to my own experience, most students in this class can list formulas and get results. However, if you want to analyze why subtraction is used, most students can't say it well, just their most direct feelings. So in class, I first affirm accurately, and then suggest that teachers appreciate students who can explain their reasons to you in their own way, and let students understand how to find a number through effective activities such as drawing, putting learning tools, giving examples and communicating.