在做模拟题的第三轮高三复习中遇到一道题 :棱长都相等的一个正四面体和一个正八面体 ,把它们拼起来 ,使一个面重合 ,所得的多面体有个面 .(注 :正多面体在高中数学新教材中有专门内容 ,其中就讲了正八面体)答案是 7个 ,学生不理解 ,拿着题来让我帮忙 .相对简单的背景 ,并不复 In the third round of the third grade review of the mock question, we encountered a question: a regular tetrahedron and an octahedron whose edges are all equal, and they are put together to make one face coincide. The resulting polyhedron has a face. (Note: The polyhedron has special content in the new textbook for high school mathematics, which includes a positive octahedron.) The answer is seven. The students do not understand and hold the questions to help me. The relatively simple background does not