Dividing three digits by three digits was learned in the fourth grade of Jiangsu Education Press. In the fourth grade mathematics textbook of Jiangsu Education Press, we will learn the multiplication and division of integers, including the multiplication and division of two digits and three digits, including the operation of dividing three digits by three digits. Students need to master the basic knowledge of vertical operation methods, operation rules and formulas, and be able to complete simple mathematical calculations independently, and improve the calculation speed and accuracy through practice. So dividing three digits by three digits was learned in the fourth grade of Jiangsu Education Press.