1, the whole and part can be known by counting and comparing the number of two sets, but the class inclusion relationship between the whole and part is uncertain.

2. In the early stage, you can distinguish the size, just as much, and you can know the order in the middle stage.

3, you can take it out according to things, and there is the concept of number order. If you know that 3 is greater than 2, you can compare the sizes of numbers.

4, can accurately distinguish height, thickness, length, and can be sorted in a certain order.

5. Be able to distinguish between the front and the back, and learn to distinguish between the left and the right with self-centeredness.

6, can know rectangle, ellipse, trapezoid, diamond, etc.

Characteristics of middle-class children:

1, the obvious improvement of children's activity level requires more abundant and substantial activity space.

The action ability of the children in the middle class has been obviously developed, the scope of children's activities has been greatly expanded, and their enthusiasm for activities has been greatly improved.

2. With the great improvement of children's game level, it is necessary to continuously expand the game space.

Middle-class children like symbolic games very much. They often imagine themselves as a specific role in the game. They also like to be accompanied by actions and dolls, and they also like to tell the same story over and over again.

3. The autonomy and initiative of children's further development need a relaxed and safe exploration environment.

The autonomy and initiative of middle-class children's activities have been further developed. They can put forward their own activity ideas, have the enthusiasm and ability to actively participate in activities, and strive to complete their chosen activities.

4. The development of children's peer communication needs and abilities needs a good social development atmosphere.

Children's exposure to games is gradually increasing, and the level of games is constantly improving. This provides certain conditions for the development of children's social communication ability. The ability and level of the game have been greatly developed, and the cooperation with peers has gradually developed.

5. The improvement of children's imagination needs more space for expression and creation.

Children's imagination plays a very important role in their various activities.