Math Strings

What are Math Strings?
They're groups of mental math problems that build on each other in some way.

How I Do Them:

• The kiddos sit "theater seating."  Everyone's chair faces foreword (which involves everyone moving their chair because of how my groups are set up) and they have nothing in their hands.
• On chart paper, I write a problem.
• When kiddos have an answer, they make a sign-language letter a, putting their thumb on their mouth (I don't know how to better describe it!)  This shows me they're ready and helps them to not blurt out the answer.
• I call on one kiddo for the answer and write it down, not saying if it's correct or not.
• I ask everyone if there are any other answers and write those down too.
• I call on kiddos to explain how they got their answer and record on the chart paper what they did, putting their name next to it.
• I have 3-5 kiddos give explanations.  The more difficult the problem, the more strategies I do.
• If the strategy I'm trying to get them to doesn't come up, I bring it up as my strategy.
• At the end, if I want them to know the name of a certain strategy, I tell them "what mathematicians call" the strategy some of them were using.  For example, "I want to teach you a new name for a mental math strategy.  Mathematician's call Kevin and Bryan's strategy compensation." (pointing to where I had written Kevin and Bryan's explanations earlier).

The blurred out parts are their names.  "M.F." means memorized fact.

Do you believe the kiddo who said 18 x 3 was a memorized fact?  No, me neither, but I still put it up!
At least no one said 48 x 3 was a memorized fact!

Although I knew about these last year, I only did it once or twice.  I'm doing them almost every day in math now and am getting FANTASTIC mathematical thinking from the kiddos!  

Bonus:  They LOVE it. The one day we didn't do it last week, they were asking why.  Every time I get their attention during math for a transition, they ask if it's mental math time.  I love the excitement!