Division and combination of 2-5, arranging the composition of numbers within 10 into a single unit, and teaching the composition of these numbers according to the idea of division and combination is an important idea, a common method to understand the objective world, and a strategy to learn mathematics.

The switching formula is 2:

2 can be divided into 1 and 1, 1 and 1 to synthesize 2. 2 can be divided into 2 and 0, and 2 and 0 can synthesize 2. 2 can be divided into 0 and 2, and 0 and 2 can synthesize 2.

The switching formula is 3:

3 can be divided into 1 and 2, and 1 and 2 can synthesize 3. 3 can be divided into 2 and 1, and 2 and 1 can synthesize 3.

3 can be divided into 3 and 0, and 3 and 0 can synthesize 3. 3 can be divided into 0 and 3, and 0 and 3 can synthesize 3.

The switching formula is 4:

4 can be divided into 1 and 3, and 1 and 3 can synthesize 4. 4 can be divided into 3 and 1, 3 and 1 to synthesize 4. 4 can be divided into 2 and 2, and 2 and 2 can synthesize 4. 4 can be divided into 4 and 0, and 4 and 0 can synthesize 4. 4 can be divided into 0 and 4, and 0 and 4 can synthesize 4.

The switching formula is 5:

5 can be divided into 1 and 4, and 1 and 4 can synthesize 5. 5 can be divided into 4 and 1, 4 and 1 to synthesize 5. 5 can be divided into 2 and 3, and 2 and 3 can synthesize 5. 5 can be divided into 3 and 2, and 3 and 2 can synthesize 5. 5 can be divided into 5 and 0, and 5 and 0 can synthesize 5. 5 can be divided into 0 and 5, and 0 and 5 can synthesize 5.

We learned the division of numbers 2, 3, 4 and 5. We first learned about division through teaching AIDS, and then let the children use their own bodies (fingers) as learning tools to divide.

In teaching, children are divided into one point, posing and talking, and every link is orderly and serious. Then, let the children go home and use different learning tools to make a pendulum and score a point to strengthen their memory.

Mathematical concept

Mathematical concept is the reflection of the quantitative relationship and the essential attribute of spatial form in objective reality in the human brain. The research object of mathematics is the quantitative relationship and spatial form of objective things.

In mathematics, the color, material, smell and other attributes of objective things are regarded as non-essential attributes and discarded, and only the same attributes in shape, size, position and quantity are retained. In mathematical science, the meaning of mathematical concepts should be precisely defined, so mathematical concepts are more accurate than general concepts.