As previously mentioned, our district has the fortunate opportunity to train teachers on the CCSS. In addition to discussing RICH problems and how they can be used in our own classrooms, we conduct Number Talks. We use the book Number Talks: Helping Children Build Mental Math and Computation Strategies, Grades K-5, by Sherry Parrish as a resource. Number Talks were designed to improve students' mental computation skills and number sense. Inside Mathematics is another fantastic resource that shows how different teachers in varying grade levels apply Number Talks to their lessons. In fact, this is a wonderful website that allows you to see teachers in action applying the Common Core Practice Standards! Woo!
Anyway, we have been doing our best to introduce these talks into our classroom. In my room, students sit together right in front of the board. I tell them to summon their inner Kindergartner, which they giggle at. We have only had time for a couple "formal" Number Talks, but we are beginning to apply it in all aspects of our day when answering questions verbally. Here is an example of how my students were able to solve a basic addition problem using mental math and their process for doing so:
Are they stellar? Probably not. My students were looking at me like I was a crazy person that day. They didn't quite understand why understanding how to compose and decompose numbers is so important. Many said, "I put them on top of each other and added. I also carried the one." My point was that I wanted them to know what "carrying the one" actually meant. As we do more, they do improve, and I can see it translating in other areas of math. They are really starting to think about the VALUE of the numbers.
I plan on doing more complex problems as we go and seeing how they improve. I told them I would keep their original posters so we can compare them to how they are doing in a few months. They have already drastically improved! If you don't do Number Talks in your classroom, I highly recommend you look into incorporating them every now and then, especially in younger classrooms!