If there is no answer to the fill-in-the-blank questions in the third grade math exercise book, it may be because the teacher wants students to use their knowledge and thinking ability to solve problems. This kind of topic aims to cultivate students' problem-solving ability and creativity through autonomous learning and thinking. By filling in the answers themselves, students can better understand the learning content and improve their knowledge level through the revision and reflection of wrong questions. In addition, teachers can also give reference answers after class for students to compare and discuss. If you have any questions about the answer to a specific topic, you can ask the teacher or discuss it with your classmates for a better understanding.