For junior two students, it is very important to choose suitable textbooks and problem sets for consolidating basic knowledge and improving mathematical thinking ability. Here are some suggestions:

Textbooks: You can choose the textbooks of well-known publishing houses such as People's Education Publishing House and Beijing Normal University Publishing House, which are relatively authoritative and moderately difficult, and are suitable for second-year students. At the same time, according to children's interests and characteristics, you can choose some teaching materials with pictures and vivid examples to stimulate children's interest in learning.

Problem Set: You can choose some classic problem sets, such as Daily Exercise of Mathematical Olympiad in Primary School and Selected Problems of Intellectual Development in Primary School. These problem sets are moderate in difficulty and diverse in topic types, which are suitable for second-year students to practice. At the same time, you can also choose some special training questions for second-grade mathematics, such as "Training Questions for Mathematical Thinking in the Second Grade of Primary School" to strengthen children's mathematical thinking ability.

Auxiliary materials: You can choose some auxiliary materials such as math games and popular math books, such as interesting math games and little mathematicians, which can help children learn math in a relaxed atmosphere, improve their interest in learning and expand their knowledge of math.

Other suggestions: You can choose some representative papers and assignments, such as final exam papers and math contest questions, which can help children understand the application scenarios and exam forms of math knowledge and improve their ability and self-confidence. In addition, you can also participate in some extracurricular remedial classes or math competitions to enhance your child's math ability and broaden your child's math vision.

In short, it is very important for sophomores to choose suitable textbooks and problem sets. According to children's interests and characteristics, we can choose some lively and interesting teaching materials and problem sets to stimulate children's interest in learning and improve their mathematical thinking ability and exam-taking ability.