Moreover, you can communicate with your child and ask him if he has any difficulties in his study, and if he has any emotional problems on weekdays, because the math exam in the third grade is not very difficult. Maybe the child didn't study hard, and he must have encountered some difficulties in his study that led to this result.
You can also ask your child if he feels unwell during the exam, which leads to the exam. The test of the results can be a long-term observation process, rather than just judging some reasons for a bad exam.
If it is really because you can't learn, you can tutor him and tutor yourself. Because it is not practical to apply for classes now, mathematics in grade three is relatively simple. If you have the ability to make up lessons for him, just make up lessons for him directly.