At present, there are many platforms that have videos of math lectures, and they are full sets. From the first grade of primary school to the third grade of high school, the price comparison system can be said to exist, but some textbooks are incomplete, which is one of the many shortcomings of our domestic textbook system, such as the People's Education Edition, Beijing Normal University Edition, Jiangsu Education Edition, Hunan Education Edition, Yilin Edition and Foreign Studies Edition. So if you want to watch the video, you'd better find out all the synchronized courses, otherwise it's not systematic to watch one thing in the east and one thing in the west.