This document provides an introduction to fundamental concepts in algebra including sets, intervals, unions, intersections, and absolute value. It defines what sets, elements, unions, and intersections are. It explains the differences between open, closed, and empty intervals. Examples are provided to demonstrate finding unions and intersections of sets, writing intervals in set-builder notation, finding intersections of intervals, evaluating absolute values, and calculating distances on the number line. Students are assigned related questions and a worksheet to practice these concepts.