This study explored how two professional development approaches to reforming math instruction with different mechanisms for fostering change might have valuable synergies when used in tandem to support take-up, i.e., teachers' acceptance, adoption, and incorporation of ideas into practice. This investigation of Practice-Based Professional Development and Collaborative Lesson Design found that take-up was a recursive process that occurred across both PD types as teachers iteratively moved between building and deploying knowledge. Both overarching and practice-specific struggles occurred during enactment, triggering shifts back to knowledge building. Struggles associated with learning to facilitate productive struggle included making sense of student thinking, identifying and providing appropriate scaffolds without lowering the cognitive demand, and helping students move from intuitive to mathematical arguments. [For the complete proceedings, see ED630060.]