Decomposition and combination of 1 and review 9.

2. Learn the decomposition and combination of 10 through children's practical operation.

3. Let children know more about the inclusive, complementary and reversible relationship between quantity and quantity, and lay the foundation for learning addition and subtraction.

Preparation: one set of teacher's demonstration board and one set of children's hands.

First, the beginning.

1, review odd and even numbers within 20. Let the children index the square with their hands.

2、4、6、8、 10 - 1、3、5、7、9、

2. Let the children use the stairs on the board to put out the decomposition and combination of 9. Teachers and children dictate the decomposition of 9 while operating.

Second, learn the decomposition and composition of 10.

1, please count the number of stairs on the basis of 9: 10 decomposition and combination, which can be divided into 9 and 1, 8 and 2, 7 and 3, 6 and 4, 5 and 5, 4 and 6, 3 and 7, 2 and 8, 1 and 9.

2, children's operation, teachers in the operation panel to demonstrate and tour guidance.

3. Ask individual children to be small teachers. By going up the stairs to demonstrate the decomposition of 10, and comparing the answers with other children, the teacher will tour to guide.

4. The teacher asked the children to dictate the splitting formula of 10 according to their own calculations, and the teacher recorded it on the blackboard.

Third, organize the plug-in board.

Put the small chess on the chessboard, the children classify the food according to its color, and then give it to the teacher for examination.

This is the decomposition and combination of 10. See if it can be changed to 15.