From the beginning to the present, I have been engaged in mathematics teaching in the lower grades of primary schools. In recent years, I have also deeply realized that if a child's computing ability is not strong, it will have a great impact on his overall math performance. Therefore, we also attach great importance to the cultivation of students' computing ability in our usual teaching. How to cultivate children's computing ability? I think the focus is on the following aspects. First of all, we should master the formulas of "addition and subtraction within 10" and "addition and subtraction within 20". As a key primary stage, the primary learning of addition, subtraction, multiplication and division will have a far-reaching impact on students' further study in the future. Teaching practice tells us that any complex problem is composed of a simple one. Whether it is the multiplication and division of two digits, the multiplication and division of two digits, or other more complicated calculation problems, their foundations are all caused by the two basic knowledge of "addition and subtraction within 10" and "addition and subtraction within 20", which is the formula of 99 multiplication and cannot be blurted out without thinking. If you don't master "addition and subtraction within 10", "addition and subtraction within 20" and "99 multiplication formula", you will be unhappy and inaccurate in middle and high grades. Second, strengthen the training of oral ability. "Elementary School Mathematics Syllabus" points out: "To cultivate students' computing ability, we should pay attention to basic oral arithmetic training. Oral calculation is not only the basis of written calculation, estimation and simple operation, but also an important part of calculation ability.