Because there are always some wrong questions in students' homework and exams, especially in primary school mathematics teaching, if these wrong questions are not handled well, they will affect teaching efficiency to a certain extent. Therefore, how to effectively use the wrong questions in primary school mathematics has become the main concern of teachers today. This paper expounds how to make effective use of wrong questions in primary school mathematics. 1. Intelligently guide "wrong points" into "bright spots" in primary school mathematics teaching, and promote the effective formation of students' mathematical knowledge. Teachers should skillfully turn students' "wrong questions" into "bright spots", analyze and study the wrong questions effectively, guide students to use the wrong questions effectively, and let students participate in the application of the wrong questions from different angles. Teachers can't blame students blindly when they make mistakes, which will not only hurt students' self-esteem, but also reduce students' learning efficiency and fail to achieve the expected results. Therefore, skillfully turning "wrong questions" into "bright spots" can not only reduce wrong questions in primary school mathematics teaching, but also greatly improve students' research ability on right and wrong issues and promote the effective formation of their mathematical knowledge. Second, the wrong questions are reorganized into a group of wrong questions. For primary school students, because of their age, they simply correct the problems existing in their usual exercises, without in-depth research and recording wrong questions. Some students like to have fun. In order to be lazy, they don't even correct the wrong questions pointed out by the teacher, and similar problems will still make mistakes when they appear again. Therefore, teachers should reorganize the wrong questions into a set of wrong questions, record all the students' usual wrong questions, analyze the mistakes and establish a set of wrong questions, which can not only help students understand their mistakes, but also provide effective basis for students to consolidate their mathematics knowledge. In addition, after the completion of the wrong question set, teachers should make periodic revisions, add some new wrong questions that students appear, so as to avoid complacency, and distribute the wrong question set to students for them to read and browse frequently, so as to effectively play the role of the wrong question set. It can be seen that grouping wrong questions into a group of wrong questions can not only reduce students' error rate, but also improve students' correct rate of doing questions and improve teaching efficiency. Third, cultivate students' habit of writing about math diary. In the process of mathematics learning, primary school students will always encounter corresponding confusion in solving problems, but some students are unwilling to use their brains, and most of them just skip and wait for their classmates or teachers to answer. This will not only improve their math problem-solving ability, but also affect their future math learning effect to some extent. Since mathematics learning is one step at a time, we should go down step by step to improve our learning efficiency. Therefore, teachers should cultivate students' habit of writing math diary, so that students can write it down when they are confused and when they solve a difficult problem. In this way, in the future study, students can make reflective learning through their own records, which can not only overcome their own thinking obstacles, but also record and analyze their own gains and losses through math diary, so as to better understand their own problems and correct all kinds of mistakes and bad habits in solving problems, so as to improve their ability to solve problems and make their thinking more profound and rigorous. To sum up, because the cognitive ability of primary school students is not perfect enough, it is normal to make mistakes in math exercises. As a primary school math teacher, in order to make effective use of wrong questions in primary school math, we should first establish a correct view of wrong questions, regard students' wrong questions as valuable resources, stimulate students' thinking with wrong questions, and guide students to establish self-confidence in learning. In addition, teachers should organize the wrong questions into a set of wrong questions, let students read and browse frequently, and guide them to examine the internal relations of math problems from multiple angles and in all directions, so as to reduce the rate of students' wrong questions, cultivate students' habit of writing math diary, and let students learn reflective through their own records, so as to effectively play the role of wrong questions and lay a solid foundation for students to learn math well.