1. Accuracy: First of all, teachers need to make sure that their answers are correct. If the answer is wrong, then students will study according to the wrong answer, which will have a negative impact on their study.

2. Consistency: Teachers need to keep the consistency of grading when correcting homework. For example, for the same type of mistakes, the same deduction should be given. This can avoid students' doubts about their grades.

3. Timeliness: Teachers should finish correcting homework within the specified time, so that students can know their learning situation in time and adjust their learning methods in time.

4. Feedback: When correcting homework, teachers should not only point out students' mistakes, but also give suggestions for correcting them. This can help students better understand the causes of mistakes and improve their ability to solve problems.

5. Encouragement: Teachers should give students appropriate encouragement when correcting homework. Even if students don't do their homework well, they should find out what they have done well and give them praise. This can stimulate students' enthusiasm for learning.

6. Individualization: Each student's learning ability and progress are different. Teachers should take this into account when correcting homework and give personalized opinions and suggestions.

7. Fairness: Teachers need to ensure that every student is treated fairly when correcting homework. There should be no prejudice or discrimination against students for some reasons.

8. Meticulousness: Teachers need to check every detail carefully when correcting homework. For example, whether the students' answers are complete and whether the calculation process is correct.

Generally speaking, primary school math teachers need to be accurate, consistent, timely, feedback, encouragement, personalized, fair and meticulous in correcting homework.