No, fourth-grade children are not good at math, which means that they didn't lay a good foundation, didn't learn efficiently and didn't develop good study habits in their lower grades. The knowledge of the fourth grade is not difficult. As long as children work harder and spend some time, they will certainly be able to lay a good foundation in future study. A primary school is a school where people receive primary formal education. It is an important part of basic education and belongs to the category of nine-year compulsory education.