Sixth grade. Generally speaking, Gaussian mathematics is from grade six to grade six. Gaussian mathematics is the frontier mathematics curriculum in primary schools, which includes extracurricular mathematics in primary schools and forms a knowledge tree system with seven horizontal and six vertical. The seven sections include: counting tree, calculation tree, combinatorial mathematics tree, application problem tree, geometry tree, crossword puzzle tree and number theory tree. There are six grades, namely primary school grade 1 to 6.