Number of Cases

How many cases there are gets confirmed by writing them out. Questions writing out ways of choosing where order does not matter and ways of arranging where it does and totaling them, questions drawing from a set holding several of the same kind, routes along a grid of streets, and questions with stages piled up as with coins or dice are all counted as word problems.

A color present in two or more can be counted as one case when two of that color are taken. Miss that and only pairs of different kinds get written out, and the total falls short. Whether a pair of matching colors stands among the cases written out is what separates them.

Number of Cases is gathered into this one lesson, and the center is confirming by writing out rather than by an expression. From Units of Volume the eye moves off what is being counted and onto the name given to one and the same quantity.