1. The student has just entered school for one month. Although they have learned some knowledge in preschool, their in-depth understanding of knowledge and their ability to speak complete sentences still need training. Therefore, students are very willing to put their energy into mathematics activities with their existing knowledge level.

2. Students have a certain understanding of the significance of subtraction in preschool education, but it is difficult to understand the formula of subtraction. Most students can easily master the subtraction of one digit, and the accuracy needs to be strengthened.

Students have some simple life experience of addition and subtraction before going to school. However, the thinking mode of first-year students is mainly image, and the meaning of addition and subtraction is still abstract, especially the meaning of subtraction with the number 0 and the reciprocal relationship between addition and subtraction, which is difficult for beginners to understand. Therefore, in teaching, according to students' age characteristics, starting from students' existing experience and foundation, taking familiar, novel and interesting contents as raw materials, the abstract concepts are transformed into things that students can easily understand, and the process of learning addition and subtraction is combined with the process of solving problems, thus helping students understand the significance and application value of addition and subtraction operations.