把一个五边形剖分成沿整条边相邻接的三角形,设在边上再加4个剖分顶点,内部设置3个剖分顶点．问可将这个五边形剖分成多少个三角形?有人说这道题太简单了,画出图来数一数不就行了么!画出图1,数得13个三角形．但剖分方式不止这一种,其他剖分方式结果如何呢?再画一图,如图2,一数也得13．那么,我们是否可以断言：本题的答案是13呢? Divide a pentagon into triangles adjoining the whole edge, and add four vertices on the edge, and set three subdivisions inside. Q. How many triangles can be broken into this pentagon? Some people say that this question is too simple. Draw a picture to count and do not do it! Draw 1 of the figure and count 13 triangles. However, the method of splitting is more than this one. What about the results of other splitting methods? To draw a picture again, as shown in Fig. 2, one score has to be 13. So, can we assert that the answer to this question is 13?