1. Fractions and decimals: Grade five students need to master the basic concepts, operation rules and expressions of fractions and decimals. This may be a challenge for many students, especially those who haven't mastered integers and decimals yet.

2. Geometry: With the improvement of grade, students need to learn more complex geometry, such as polygons and circles. They need to know the properties and characteristics of these figures and be able to calculate their perimeter, area and other related attributes.

3. Algebraic expressions and equations: In the fifth grade, students began to contact algebraic expressions and equations. They need to learn how to use letters to represent numbers, variables and functions, and to solve simple linear equations.

4. Practical problems and mathematical models: The fifth-grade mathematics curriculum usually involves the solution of practical problems. Students need to learn to turn real-life situations into mathematical problems and build mathematical models to solve these problems. This may be abstract and difficult for some students to understand.

5. Logical reasoning ability: Math problems in grade five usually require students to have strong logical reasoning ability. Students need to learn to use what they have learned to reason, analyze and prove in order to solve complex mathematical problems.

In order to help children overcome these difficulties, parents and teachers can take the following measures:

* Ensure that children master basic mathematics knowledge and lay a solid foundation for more advanced learning.

* Consolidate children's understanding and skills through examples and exercises, and help children gradually build confidence.

* Encourage children to ask questions and think, and cultivate their curiosity and exploration spirit.

* Use lively and interesting teaching methods to make mathematics more interesting and attractive.