1. The knowledge content is richer and more complicated: the knowledge content of mathematics in Grade Two is richer and more complicated than that in Grade One, involving more mathematical concepts, theorems and methods. For example, second-year math students will learn new knowledge points such as quadratic root, addition, subtraction, multiplication and division of fractions, and plane rectangular coordinate system.

2. The problem-solving methods and skills are more demanding: the problem-solving methods and skills of junior two mathematics are more demanding, requiring students to have strong logical thinking ability and problem-solving ability. For example, junior two students will learn how to solve geometric problems by algebraic methods and how to solve practical problems by using the properties of functions.

3. The requirement for abstract thinking ability is higher: the knowledge points of junior two mathematics often involve abstract concepts and theories, requiring students to have strong abstract thinking ability. For example, junior two students will learn the concepts, properties and images of functions, which requires students to understand and use these abstract concepts.

4. The difficulty of application problems increases: The difficulty of mathematics application problems in Grade Two is higher than that in Grade One, which requires students to have strong practical application ability. For example, students in Grade Two learn how to use what they have learned to solve mathematical problems in real life, such as calculating area and volume.

5. More diversified test questions: Compared with grade one, the test questions of grade two mathematics are more diversified, including multiple-choice questions, fill-in-the-blank questions, solution questions, proof questions and other forms. This requires students to have a strong ability to take exams while mastering basic knowledge.

In a word, the difficulty of mathematics in Grade Two is higher than that in Grade One. Students need more study and training in knowledge content, problem-solving methods and skills, abstract thinking ability and so on to adapt to more difficult learning tasks.