For each big idea, the text will unpack for teachers the big ideas and how to look for student thinking around these ideas to make instructional decisions. It will address the questions: What is the big idea and why is it important? How do students learn this big idea? What should I look for in student thinking and strategies? Further, each activity or task will be accompanied by ideas for how to launch and how to facilitate discussion after the activity. Activities in the three areas - visual math, play, and investigation - will be provided as reproducibles.