The cubic power of mathematics in the first volume of the sixth grade of Jiangsu Education Press. Cubes are learned in the sixth grade. When learning the area of a square in the fifth grade, the letter formula is used to indicate that the area of a square is equal to the square of a, and the volume of a cube is multiplied by the side length and then multiplied by the side length. This formula is expressed by letters, and the cubic of a is used. This is the only knowledge point with cubic power in primary school. Students only need to understand that a cube is a multiplication of three identical numbers.