© Philip B. Yasskin, 2008-11.
Last updated March 20, 2011
Abstract
Students count the number of faces F, vertices V, and edges E, and compute the Euler number (pronounced oiler) which is defined to be F + V - E. The students quickly conjecture that the Euler number is always 2. After they are convinced of this, the instructor tells them it's false and challenges them to find a shape whose Euler number is not 2.
© Philip B. Yasskin, 2008-11.
Last updated March 20, 2011