In fact, in the early stage of children's mathematics enlightenment, children's thinking characteristics are concrete and vivid, and it is difficult to understand the abstract concepts of mathematical symbols. Therefore, before learning addition and subtraction, you can learn the composition of logarithm to avoid children directly performing abstract symbolic operations.

The composition of a number means that a number can be divided into several parts and several parts can be combined into a number (total). The composition of a number includes decomposition and synthesis.

According to the law of children's cognitive development, children can try to learn the composition of numbers (also known as division and combination of numbers) from the age of five. After a large class, children can basically master the division and combination of numbers within 1- 10, as well as addition and subtraction.

Then, how to guide children in the composition stage of learning numbers?

1, starting with small numbers, let children know the composition number and understand the meaning of the composition.

Take four peaches and divide them into two plates. At the same time, the combination of the numbers 4 is written as 1 and 3. Then, tell the children that the two separate lines "∧" mean "points", which means that 4 can be divided into 1 and 3.

Then put the peaches together in a plate and write the combination of 1 and 3 to get 4. Tell children that the symbol "∨" means "combination", which means 1 plus 3 equals 4.

2. Let the children operate in kind.

Let the children do it themselves, first of all, they can verify the correctness of the known results, and at the same time, through repeated operations and exercises, they can deepen their understanding of the points and meanings.

Besides sharing peaches, we can also give children something easier to operate, such as buttons, snowflakes, cartoon toys and so on.

3. Guide children to discover other methods of separation and integration.

When the child has fully understood and mastered a way of dividing and combining a number, then try to guide the child to discover other ways of dividing and combining. For example, there are several different ways to divide four watermelons into two bamboo baskets.

4 can be divided into 1 and 3, and can also be divided into 2 and 2; 3 and 1, meanwhile, 1 and 3; 2 and 2; 3 and 1 add up to 4. You can also change watermelons into objects that are easier to operate, such as building blocks, beans, sticks and so on. Let the children practice and understand different points.

4. Guide children to discover the equivalence, complementarity and interchange in the composition of numbers.

When children can complete all combinations of a number, they will sum up various combinations. Let children discover the rules through different writing methods. For example, the number 5 is divided and combined.

Let the children fill in or write all the combinations of a number by themselves, and let them sum up the rules of combination.

√ A number can be divided into two parts, and the sum of the two parts is equal to an integer, which is the equivalence relation in division and combination.

The number of √ 1 is divided into two parts, one part is arranged in sequence and the other part is arranged in reverse. At the same time, the number of 1 part is greater than 1(+ 1), and the other part is less than 1(- 1), while the total number remains unchanged.

√ In the division formula of numbers, the positions of two partial numbers are interchanged, and the division formula still holds. This is the exchange relation in the switch formula.

By learning the division and combination of numbers, let children understand that an integer is divided into two parts, which contains the above three relationships.

Let children know the composition of numbers in operation and experience division and combination. From physical separation to digital separation and integration, we can understand the composition of numbers from the process of digital separation and integration. Through such activities, I feel the composition and connection of numbers.

The composition of numbers, the basis of addition and subtraction, gives children a concrete and intuitive feeling through the composition of physical exercises, and also helps children understand the abstract concepts of "+"and "-"symbols in mathematics, laying a good foundation for the introduction of addition and subtraction.