These exercises are written and revised according to the outline, and the content of the questions will not change because of the difficulty.

Mathematics is the study of patterns, or a process of patterning. Mathematics is to abstract a specific problem into a pure mathematical problem. The solution of this abstract problem has practical significance and is helpful to solve practical problems. Therefore, mathematics has two attributes, namely abstraction and reality (or application). When children learn mathematics, they must start with the concrete things they are familiar with in life and gradually start the abstract process of mathematics. It can't be called mathematics just to solve specific problems. It is against the essential attribute of mathematics to teach abstract mathematical operations without starting from specific things and divorced from specific practice. Children are in the period of germination and initial development of logical thinking, and it is also the period of initial formation of mathematical concepts. Mathematics knowledge has a strong logic and abstraction, and learning mathematics can exercise the logic and abstraction of children's thinking.