Jingyu. Com is an excellent website for studying mathematics, physics and chemistry. Basically, the basic topics that primary and secondary school students usually encounter are all involved. As long as they can't type in the search bar, they can search and download test papers, which is very convenient. Every problem has a detailed analysis, and all kinds of problems are classified. According to this classification, websites can provide topic training for such problems. There are more than 10 thousand math papers to choose from, which is very convenient, but some of them have already started charging.