How to teach two digits plus one digit in first grade mathematics?

Here is a lesson plan for you to read:

Teaching process:

First, check the import.

1, respectively showing dictation cards: 8+6= 7+9= 8+4=

20+ 15= 16+50=

2. Say the steps of oral calculation: 20+(7+5)= 30+(5+5)= 30.

3. Demonstration courseware "",showing: 27+2=

Say the name, say the process of verbal calculation. (First 7 plus 2 equals 9, then 20 plus 9 equals 29. )

Continue to demonstrate the courseware, and the clever little monkey also came to our study. Seeing that we all know that 27 plus 2, he took the second addend "2" away and replaced it with "5", so the problem became 27+5. Can it still count? Let's ask the students to solve this problem.

Second, explore new knowledge.

1, self-study attempt

Students put their own sticks and explore the calculation method of 27 plus 5.

2. Group switching operation.

3. Calculation method of collective communication

The teacher wrote on the blackboard to match the students' speech.

(1) First of all, 7 plus 5 equals 12. Then, 20 plus 12 equals 32.

(2) Divide 5 by 2 and 3, 3 plus 27 equals 30, and 30 plus 2 equals 32.

(3) Divide 27 by 22 and 5, 5 plus 5 equals 10, and 22 plus 10 equals 32.

(4) Starting from 27, add 1 1 plot upwards, and 5 is 32.

Step 4 compare

Which method is simpler?

Students express their opinions.

The teacher continues to demonstrate the courseware and the students describe the steps of oral calculation. (27 plus 5, first add 7 and 5 to get 12, then add 20 and 12 to get 32. )

5. Summary

Teacher: What's the difference between the problem we calculated today and the problem of adding two digits and one digit before? What's the name of this attachment? (Carry addition) Yes, today we are going to learn the carry addition of two digits plus one digit.

Teacher: What are the characteristics of the number of carry addition? (The original number of the tenth place has increased by 1) Why? (When the digits add up to ten, give ten digits 1 tens, so there are more digits on the ten digits 1. )

Third, consolidate the practice.

1, complete the question 1 on page 66.

Display: 5+35=

What's the difference between this problem and the example? What's first? What is it? Talk to each other at the same table and call the roll.

Emphasis: whether it is two digits plus one digit or one digit plus two digits, we should pay attention to adding up the digits first.

2. Do the second question.

48+6= 8+63= 74+9=

Review after students finish independently: talk about the process of oral calculation.

3. Oral calculation: 7+6= 9+5= 6+4=

27+6= 39+5= 6+54=

Compare the oral calculations at the same table and tell each other what the characteristics of each group of questions are.

4. Open questions