The desire to persuade students to avoid strictly memorizing formulas is a recurring theme throughout discussions of curriculum and problem solving. In combinatorics, a branch of discrete mathematics, problems can be easy to write--identify a few categories, add a few restrictions, specify an outcome--yet extremely challenging to solve. A lesson on counting combined sets is presented in the article. It is based on a short activity (dealing with fruit) and group discussion that developed into increasingly student-led conversation.