## Thursday, October 10, 2013

### Estimating and Counting Routines Part 4

New to my estimating and counting routines series?  Click here to start from part 1!

I did this estimating and counting routine with a group of second graders who need a bit more practice with some early numeracy ideas.  I also knew that they would be beginning to work on counting by 25's in class as they got into their money unit and wanted to give these 5 kids a head start on this idea.

To do this counting and estimating routine, I used my bucket of buttons.  Kids love using these for math because they are super engaging and you can keep adding to your set as you find unique buttons.  I have even had kids bring in more buttons to add to the collection.  I also read them The Button Box when we first start using the buttons.

 I dumped out what I estimate to be more than 125 but less than 200 buttons.  It took me some practice to be able to do this because the tiny buttons can make it tricky!
After dumping out these buttons, I gave kids about 20 seconds to look at the collection and make an estimate about how many buttons they thought were there.

I then pulled 10 buttons aside and asked kids to think about if this is 10, how many are there alltogether.

 After doing this, I let kids adjust their estimate if they wanted to.

 Here is a look at each student's initial estimate and their adjusted estimate.  As you can see most students increased their estimate after seeing what a pile of 10 looked like but one kid actually decreased their estimate.

I then asked the kids to think about how many we could each take from the pile without running out.  They looked very unsure so I did some further prompting.

"Is there enough for us to each take 10?"

"Yes!"

"Is there enough for us to each take 20?"

"Yes!" (I thought this was funny since none of them estimated the quantity was over 100 yet they were sure that we could each take 20.  Six of us at the table X 20 each = 120.

"Is there enough for us to each take 30?"

(mixed words of uncertainty)

"So if there is enough for us each to take 20 but you are not sure there is enough for us to each take 30, how many should we each take?"

"20"

"25"

"yeah 25 sounds good"

Hmmm.... let's see, one of my goals for this lesson was to introduce the idea of counting by 25's and here I have a few students suggesting that we each take 25.  BRILLIANT!

We decided to each take 25.  We briefly talked about how to take about 25 into our own area and then quickly count and confirm how many were actually there.  We also talked about taking turns and not grabbing.  Then I turned them lose to each take 25.

 Kids working on taking 25 buttons

 One student's collection of 25 buttons
Once we each had 25 buttons, we needed to figure out how many buttons we had altogether.  I started and we worked on counting around the circle.  Having the buttons as a visual model was VERY helpful as kids thought about putting fives together to make tens.  One particular student was very stuck and needed to use a 100 bead string to help her.  After using it she was able to connect what she did back to the piles of beads.

 After counting by 25's around the circle a few times we recorded the numbers on the board and looked for patterns in the numbers.  A great way to get kids to practice counting by 25's multiple times is to have them check and see if it matters what person starts the counting.  Of course they quickly realize it doesn't matter at all but in the meantime they get some extra practice.
After we each had 25 buttons, there was a small pile remaining in the middle.  A student suggested we count them by 2's (which is another important second grade skill!)

 A student lined up the remaining beads and counted them by 2's.  I had another student do it after to check her work, and of course give one more student some practice with this skill!
All we had left was to figure out 150 + 18.  I recorded this equation on the board and gave kids a few minutes to think about it and asked them to give me the ready signal when they knew the answer.  I then had kids turn and talk to a partner about what they thought the answer was and how they knew they were right.  We then talked about different strategies kids used to figure it out.  The most popular strategies were counting on by 1's and  the idea of adding the 10 and then the 8 ones.  This was a great time to discuss efficiencies of strategies and the difference between counting and thinking strategies.

Stay tuned for more in my counting and estimating series.

Ready to read more?  Check out part 1, part 2 or part 3!