随手教具是指那些无需专门准备即可用于教学的物品。学校在购置的教具中,已经有一些如三角形,四边形,园等模型,但是还有一些更简但的几何图形,如线段,射线,角等模型,我们可以自己动手制作。所取材料方便简捷,如手电筒,废弃的电线,绳子钟表等均可作为教具,手电筒射出的光线就是射线。拉直的电线,细绳可看做直线或线段, Handy aids are those items that can be used for teaching without special preparation. There are already some models in the teaching aids, such as triangles, quadrilaterals and gardens. However, there are some simpler geometric shapes, such as line segments, rays and angles, which we can create by ourselves. The material taken is simple and convenient, such as flashlights, discarded wires, rope watches, etc. can be used as a teaching aids, flashlight injection of light is the ray. Straightened wire, thin rope can be seen as a straight line or line,