Math Centers are a perfect activity for the classroom! They allow for collaboration among students and "math talk", which is a key piece of the common core. Also, you have time to reteach and enrich students. These math centers are designed to go along with topic 7 in the Envision Math® 2.0 curriculum.
Topic 7 focuses on a conceptual understanding of subtraction and since the centers are aligned with the common core math standards, they can still be used with a different core curriculum.