This publication describes several different teaching strategies employed to enhance students' understanding of mathematics, such as working in cooperative learning groups, giving presentations based on problems that were solved, and writing about solutions that were found. This innovative approach to teaching mathematics resulted in questioning whether traditional methods of assessment were sufficient for students who had been exposed to this teaching method and led to the development of a performance assessment as a final exam for a high school Algebra II class. Organization of the exam and how students prepared for it are discussed. Results of this innovative assessment indicate that: (1) some students performed surprisingly well and were able to explain concepts in detail; (2) if a question was rephrased, students were able to do very well explaining a problem in contrast to drawing a blank on a traditional test; and (3) others did not do as well as expected, demonstrating an inability to explain concepts, but instead, relying on memorized facts and simple computation. Suggestions for test administration and an evaluation sheet for the assessment of student discussions are appended. (Author/LL)