/kloc-Euler, a Swiss mathematician in the 0/8th century, proved an interesting relationship between the number of vertices (v), the number of faces (f) and the number of edges (e) of a simple polyhedron, which is called Euler formula. Observe the following simple polyhedral model:

According to the polyhedron model above, you find that the relationship between the number of vertices (V), the number of faces (F) and the number of edges (E) is V+F-E = 2.

Test site: Euler formula.

Analysis: Firstly, according to the number of vertices, faces and edges of tetrahedron, cuboid, octahedron and dodecahedron, we can sum up the relationship among the number of vertices (v), faces (f) and edges (e).

Solution: Solution: If the number of vertices of a tetrahedron is 4, the number of faces is 4 and the number of sides is 6, then 4+4-6 = 2;

If the number of vertices of a cuboid is 8, the number of faces is 6 and the number of sides is 12, then 8+6-12 = 2;

If the number of vertices of an octahedron is 6, the number of faces is 8 and the number of edges is 12, then 8+6-12 = 2;

Then the relationship is: v+f-e = 2;

So the answer is V+F-E = 2.