Rectangular, square, triangle, circle, parallelogram, pentagon, hexagon, etc. There are cuboids, cubes, cylinders, spheres and so on.

In the design of the problem. Generally, it is a graphic connection problem. For example, which of the following reminders evolved, please connect the corresponding graphics. There is also the problem of classification. For example, the above picture belongs to rectangle, square, triangle, circle, parallelogram and so on. Fill in the table below. Then there is the problem of bricklaying. Look at the wall according to the size of the rectangle. Some bricks are missing. Therefore, in the first and second grades of primary school, students should be trained to look at pictures and graphics. The cognitive problem of graphics began to have some difficulties.

The plane figures in primary school are triangle, rectangle, square, parallelogram, trapezoid and circle. Three-dimensional graphics are: cuboid, cube, cylinder and cone. Rectangle, a mathematical term, is a parallelogram with right angles called rectangle. It is also defined as a parallelogram with four right angles, and a square is both a rectangle and a diamond. The essence of a rectangle is that two diagonal lines are equal, two diagonal lines are equally divided, two opposite sides are parallel, two opposite sides are equal, four corners are right angles, and there are two symmetrical axes (four squares), which are unstable (easily deformed). The square of the diagonal length of a rectangle is the sum of the squares of two sides, and the quadrilateral obtained by connecting the midpoints of each side of the rectangle in turn is a diamond.