Number talks are one of those things that I think every math teacher should be doing from K-12. In short number talks are a a 5-10 minute daily routine that focuses on student talk. Teachers provide thoughtful chosen questions based on strategies or topics being taught and then students share the ways they solve them. There are a couple of awesome resources available for teachers to use when thinking of starting the number talk routine in their classroom.
There are also a variety of videos on youtube that show how a number talk works and how it looks in a variety of classrooms. Here is one example below:
Some valuable information I have found is that you need to set up a safe classroom climate in your classroom and ensure students feel that accepting safety so they will share the variety of their ideas. You also need to do them everyday and you see improvement in number sense and their mental math abilities. I suggest to teachers to do 4-5 days of number talks and then ask students to share in writing rather than out loud so you can assess what students are doing for mental math strategies. You can use whiteboards or as an exit slip.
Here is another youtube video from the author Sherry Parrish - it's just over an hour but I think very powerful!
Good Luck with your number talks - please feel free to comment below with your successes, questions or comments.
Check out this blog post from Anthony at Mashup Math