Teaching objectives

1, guide students to experience the exploration process of writing two addition formulas and two subtraction formulas according to a picture and calculating the number, and feel the objective fact that changing the position of two addends has the same number.

2. Master the calculation method of addition with numbers of 6 or 7, and be able to do oral calculation correctly.

3. Cultivate students' interest and exploration spirit in learning mathematics by using "one picture and two styles".

Teaching focus

Master the calculation method of addition of 6 or 7, and be able to do oral calculation correctly. Preparation of teaching tools: courseware, title cards and sticks.

Teaching difficulties

Cultivate the initial hands-on ability, observation ability, understanding ability and the spirit of independent exploration, and initially feel the idea of simple functions.

teaching process

First, create a situation to trigger demand.

Teacher: In the process of learning mathematics, we made many interesting digital friends, and these digital friends gradually formed our mathematics kingdom. Which digital friends of Happy Mathematics Kingdom do you know? The students answered.

Teacher: The teacher wants to know the digital friends counting from 0, 1 to 20, but the teacher can't remember. Can you tell the teacher what they are? Health: Yes.

Teacher: Good. Let's count from 0, 1 to 20. Remember: count to 20 neatly and loudly. (The whole class counts from 0, 1 to 20) Teacher: The students answered really well. You're amazing!

Teacher: Since the first grade, which digital friends have we met? The students answered.

The teacher shows the digital cards 0, 1, 2, 3, 4, 5, 6 and 7 in turn. Teacher: Are these correct? The students answered. The teacher asked eight children to take a card on the stage, and asked the students to arrange themselves in a row according to the order of numbers from small to large.

Teacher: Doubt? Last class, I made two new friends in our math kingdom. Who are they? Do you remember? The students answered.

Teacher: The teacher asked two lovely children to come up and find these two new friends! Stick the new friends you have found on the blackboard.

The teacher guides the students to find 6 and 7 and paste them on the blackboard.

Teacher: Great, you are so smart! Let's meet our friends in these two classes!

Second, abstract the model and list the formulas.

Learn to write two addition formulas according to a picture.

(1) Students put sticks. (Two people are sitting face to face, and one of them is posing)

The teacher reminds the students to put 5 on one side and 1 on the other side, then let both students observe, say the meaning from left to right, and write an addition formula respectively.

(2) Students report and exchange their own addition formulas, and the teacher's process of cooperating with students is written on the blackboard: 5+ 1= 1+5= Prompt students to observe: Are the two formulas written the same? (not exactly the same)

Third, understand arithmetic and explore algorithms.

Guide the students to think: everyone writes the formula according to the same set of sticks. Why are the two formulas different? Talk to each other in pairs and then communicate collectively.

Health 1:

Because they are all observed from left to right. I saw the 5 on the right first, so the formula I wrote was 1+5.

Health 2:

I first saw a small stick on the left, and then there were five on the right, so the formula I wrote was 5+ 1. The teacher explained: Because the two students in each group sit in different directions and observe from different angles, the formulas written are different.

Fourth, exchange and display, and experience diversity.

1, let the students calculate the numbers of 5+ 1 and 1+5, and then talk about their own calculation methods.

Health 1:5 and 1 make up 6, so 5+ 1 equals 6.

Health 2: It can be counted as one in the future:

5,6,5+1equals 6.

Health 3: You can also count sticks, 1, 2, 3, 4, 5, 6. Teacher's explanation: As long as the calculation is correct, students are allowed to use their own methods, but the composition of the first number should be emphasized in oral calculation. Ask the students to tell each other what 5+ 1 is.

2. Guide students to compare: 5+ 1=6, 1+5=6. The teacher guides the students: Please observe carefully. What are the similarities and differences between these two formulas?

Derivation: In these two formulas, the number of additions is the same, the algorithm is the same, and the number of additions is the same; The positions of the two addition numbers in the formula are different, and the positions change.

Verb (abbreviation of verb) course summary

Teacher: Students, recall what we learned in this class. What do you have to share with everyone?

Health 1: I learned the addition and subtraction of 6 and 7, which can also be used to solve problems in real life.

Student 2: When you know how to calculate, you must distinguish between addition and subtraction, and be careful when calculating.

Teacher: In this class, students not only explored the addition and subtraction methods of 6 and 7, but also used them to solve problems. What a great harvest! That's all for today's class. Class is over.