Care has to be taken to use the correct Euler characteristic for the polyhedron.

This constant, χ, is the Euler characteristic of the plane.

Thus 2 is called the Euler characteristic of the plane.

Thus, its Euler characteristic is usually equal to (given that ).

These can be used in understanding and proving the product property for the Euler characteristic of a fiber bundle.

Subtracting the sum of these values from 2 gives the Euler characteristic.

Otherwise, the order is 2 divided by the Euler characteristic.

Hence its Euler characteristic is - that is, either 0 or 2.

Its Euler characteristic is 0, by the product property.

These join along 270 edges, which in turn meet at 92 vertices, with an Euler characteristic of 2.