You don't need to learn Moby's love of mathematics to learn Jin Xiong's mathematics. Jin Xiong's whole system is complete and comprehensive, and his exercise book is very good. Moby's online thinking course is mainly aimed at children aged 3- 12, covering the middle class to the sixth grade, and the class type is 1 to 12. Online work can accept children under 3 years old, and there are thinking courses that children in kindergartens and small classes can take.