Enhancing the mathematical problem solving and conceptual understanding of Year 6 students was the goal for a team of primary teachers. For this purpose, they investigated a teaching approach involving Challenging Tasks as a Professional Learning Community. The process followed by the team is outlined, and the impact on teaching and learning is described. Overall, challenging tasks were useful for facilitating student engagement in mathematical problem-solving and for building students' conceptual understanding. Recommendations are presented for those seeking to investigate the impact of challenging tasks for advancing students' mathematics engagement and learning, and cultivating 21st Century learning skills.