Poor math scores in grade three, we must first analyze the reasons. It may be because the basic knowledge is not firmly mastered, it may be because of improper learning methods, or it may be because of lack of practice. In view of these problems, the following measures can be taken to remedy them:

1. Check and fill in the gaps: review the mathematics knowledge of junior high school for three years, find out your own weak links, and review it in a targeted manner. You can do intensive training by doing after-school exercises, attending remedial classes or inviting tutors.

2. Improve learning methods: adjust learning attitude and maintain a positive learning attitude. Learn to arrange time reasonably, make a study plan, and ensure a certain amount of study time every day. At the same time, we should pay attention to cultivating our problem-solving ability and thinking, and learn to use what we have learned to solve practical problems.

3. Increase the amount of practice: Doing more math problems is the key to improving math scores. You can start with textbooks, problem sets, simulated test questions, etc., and gradually improve your speed and accuracy of solving problems. In the process of doing problems, we should pay attention to summing up the rules and form our own problem-solving skills.

4. Timely feedback: In the process of learning, we should ask the teacher questions in time and listen to the teacher's opinions and suggestions. At the same time, we should learn to check ourselves, find our own mistakes and correct them in time.

5. Develop good living habits: work and rest regularly and get enough sleep. Pay attention to a balanced diet, eat more fruits and vegetables, and enhance physical fitness. Take part in physical exercise properly to improve the ability to resist pressure.

In a word, it takes continuous efforts and time to improve the math scores in grade three. As long as you find a suitable learning method and make unremitting efforts, I believe you will certainly achieve ideal results.