In the project Collaborative Lesson Research Development (CLRD), four Mathematics II teachers together with a UPNISMED facilitator collaboratively developed, critiqued, and revised a lesson on Solving Quadratic Equation Using Quadratic Formula. The lesson utilized the approach teaching * **through** *problem solving. Teaching* **through* problem solving is an approach wherein a problem is given to the students at the start and is used as context to teach a topic as well as to develop skills and apply these skills to unfamiliar situations. It is characterized by students’ deep construction and understanding of mathematical ideas and concepts. The problem in the lesson used a real life context and it involved different ways to solve it. The nature of the problem provided an opportunity for the students to apply their previous knowledge and skills and experience thinking skills like representing, looking for patterns, and generalizing.

The study focused on the content of the problem solving activity of the lesson. How the students progressed in the problem solving process and how the teacher provided scaffolding so that the students would complete the task were the ones given particular attention. To follow up the students’ progress and the scaffolding the teacher provided during the problem solving activity, Polya’s Four Steps of Solving a Problem was used as a guide. At first, the students experienced difficulty in solving the problem. However the difficulty was addressed when the teacher provided the necessary scaffolding.

The result of the problem solving activity was an “eye opener” to the four Mathematics II teachers. They realized that the reason why the students had difficulty in solving the problem was that they were not exposing the students to problems involving multiple solutions; to problems involving the skills of looking for a pattern, generalizing and “modelling”. The problems they usually give are problems involving only one solution and an answer of numerical in nature.

The full text of the study is one of the chapters of the book titled “BOOK 1. LESSON STUDY: PLANNING TOGETHER, LEARNING TOGETHER” which will be published in print form by UP NISMED this first quarter of 2013.