The document discusses problems involving sets and operations on sets such as union and intersection. It provides two word problems as examples: 1) A class of 40 students where some prefer Japanese language, Korean language, or both. It asks how many students prefer each language in total or exclusively. 2) A survey of 50 people on ice cream flavors they like from chocolate, mango, and strawberry. It asks how many people like each flavor alone or in certain combinations. The document shows the set diagrams and calculations to arrive at the answers.