A considerable body of research shows that individuals who demonstrate a wide variety of metacognitive skills perform better on scientific problem solving. We developed a way of implementing homework in an undergraduate physics course to promote metacognitive skills. This novel homework design includes both an individual and a team phase and was implemented in a team-based learning environment. We developed a coding table to conduct both qualitative and quantitative analyses of students' expressions of metacognitive thinking. Results indicate that students' expressions of metacognitive thinking improved during the term. Data also show that team discussion helps improve metacognitive skills.