That's great. I started kindergarten at the age of five. It would be nice to be like this. This requires cultivating his interests, such as finding mathematics in life. Interest is very important, otherwise it is easy to get tired of learning. You can let him know that learning math is a great honor. Of course, the child is still young, so let him play more and spend more time with him, otherwise there will be less time in the future. Back to the topic, you can ask him to do some Olympic math problems, the kind of applied problems, and develop his thinking. You can't just focus on the thinking process without doing anything.