In order to make students deeply understand the "superfluous conditions", I created a story situation before class: Bear's mother prepared breakfast for Bear. When Bear got up, he saw a big box of yogurt, a straw and a fan on the table. Bear wants to drink yogurt. How should he choose? Can you come up and help him choose? Students are familiar with this kind of life, and they all rushed to shout out and made the right choice. Then I asked, "Why doesn't the bear choose fans?" The children made it clear that the bear doesn't need a fan to drink yogurt, and the fan on the table is redundant. At this time, I emphasized "redundancy" to make it easier for students to understand what "redundancy" is and pave the way for the next teaching.
Second, observe the situation map and explore solutions.
After students feel "redundant", I follow the method of "solving problems" in previous teaching, create situations, show the theme map, and let students observe the theme map. "What mathematical information do you know from the map and what problems need to be solved?" Students can speak actively and tell useful mathematical information and questions. After I found the question, I didn't rush to let the students answer it. But let them talk at the same table first. "What information do we need to know if there are still a few people missing?" Through the discussion at the same table and the previous understanding of "redundancy", many children soon realized that the information of "our team scored four goals" in this question was useless and redundant. At this time, I told them that mathematically useless information is called "redundancy condition". After finding useful information, the children solved the problem easily.
Third, help children find ways to improve their problem-solving ability.
In order to improve students' problem-solving ability, I help children find ways to guide students to analyze conditions, let students find useful information needed for solving problems, and then let them cover the redundant conditions in the questions with their fingers, thus strengthening children's judgment ability on redundant conditions and cultivating children's logical thinking ability.