Personally, I feel that primary schools must brush questions and practice for five or three days every day, and it is better to practice for five or three days every day. Practice once every five or three days, according to the content of the textbook. The difficulty of the topic is moderate, with both foundation consolidation and moderate expansion, which is very suitable for parents to buy for their children to practice at home. My own children have been buying it for five or three days since the first grade, and the effect is still good.