How about reading lang's new mathematical thinking target class?
After reading the online introduction, this course is about Olympic Mathematics. There are two classes a week, which are divided into two parts: application and teaching, namely, knowledge explanation and exercise explanation. Expand children's mathematical thinking and improve their ability to take exams and think. The course is based on the A and B versions of the primary school Olympic mathematics textbook "Draw inferences from one instance", which should be good.