Tag for pages that provide an example problem referenced by a number of other pages.
The summary of the page should contain the entire text of the problem (so that the problem can be referenced by greenlink). The body of the page should either contain the answer (e.g., hidden behind an 'Answer' button), or should contain a link to the page that contains the answer. The body of the page should not explain the solution to the problem, but may link to the page that does.