1. inattention: children are easily distracted and it is difficult to concentrate on one thing for a long time. In the process of doing the problem, they may be attracted by other things, leading to carelessness.

2. Not proficient in mathematics knowledge: children may encounter some difficult knowledge points in the process of learning mathematics. This will cause them to make mistakes when doing the problems, thus forming the habit of carelessness.

3. Lack of patience and perseverance: In the face of intractable problems, children may choose to give up or deal with them hastily because they are unwilling to spend too much time and energy thinking. This mentality is likely to lead to careless mistakes in the process of doing the problem.

4. Overconfidence: Some children may be overconfident in the learning process, thinking that they have mastered a certain knowledge point, which leads to careless mistakes in doing problems.

5. Lack of adequate practice: Mathematics is a subject that needs constant practice. If children do not have enough practice opportunities, the proficiency and accuracy of doing problems may be affected, and careless problems may easily occur.

6. Parents and teachers expect too much: Sometimes, parents and teachers may expect too much from their children's academic performance. This kind of pressure may cause children to be too nervous when doing problems and prone to careless mistakes.