If one thing can be done in m ways and another thing can be done in n ways, the two things can be done in mn ways. Example: A restaurant has 5 appetizers, 8 beverages, 9 entrees, and 6 desserts on the ...

https://doi.org/10.4169/math.mag.84.5.369 • https://www.jstor.org/stable/10.4169/math.mag.84.5.369 Copy URL Summary C. F. Gauss discovered a beautiful formula for ...