## Thursday, December 5, 2013

### Estimating and Counting Routines Part 5

If you are new to my estimating and counting posts, click here to start at the beginning.  I have explored many ways that I use estimating and counting routines in classrooms grades K-5 to improve a wide variety of math skills.

Today I want to share with you an estimating and counting activity that I did with a group of 5 first graders.

 The manipulative of choice today was gemstones.  These are always a big hit with kids!  I bought a multi-colored pack of them years ago and have slowly been adding to the collection over time.  They are colorful and fun and flat so they don't roll off the table!

I started by dumping out the gemstones and pulling 10 to the side.  Based on this, I asked each kid to estimate how many were on the table.  Because we have been practicing reading and writing numbers to 120, I had them each record their estimate on the whiteboard.

 Their original estimates are written in the column second from left.  Everyone estimated either 90 or 50.  I did have to enforce the no guessing 100 rule with this crew.  It is a rule I often have to pull out with young kids who estimate 100 whenever they see more than 20.
Next I asked the students if there were enough gemstones for each kid to have 10.  They all answered yes and I asked each student to take 10 gemstones.

 Each kid took 10.  When they were done, I asked them to look around and see if there was a student who I could just look and know there was 10 in their space.  These two students showed different ways to know there was 10.  One student arranged theirs into a 10 frame and the other put theirs into 2 groups of 5.  The other students quickly decided that they too needed to show their gemstones in a way that made it easy to see there were 10.
After each kid took 10, we counted by 10's and found out that 50 gemstones had been counted.  I had a student write the number 50 and we discussed what the 5 meant.  This is a great way to connect the idea of 5 tens to concrete objects.  I then let each kid go to the board and adjust their estimates based on the information we had so far.
 You can see the estimates went up quite a bit.  Some kids needed to ask for help from their peers on how to write a number of this size.  I also noticed that kids were more confident and everyone chose a different number.
I then asked if there were enough left in the center of the table for us to each take 10 more.  The kids all thought there was and went ahead and took 10 more and again arranged them in a way that it was easy to know there were 10.

We counted by 10's around the circle and found that we had 100 gemstones counted.  We also double checked our counting by counting by 20's around the circle.  The kids had never been asked to do this before but it went very well.  They quickly realized that they could think about counting by 10's to help them with this.  We also discussed the idea that it did not matter who started the counting or what direction we went around the circle, there would still be 100.  One little girl thought we should count by 5's as well (hers were arranged in more distinct groups of 5) we did that which was another great way to practice an important first grade skill.

I then let kids make one last estimate.

 You can see that our numbers are getting quite large and technically farther than what is required of first graders.  I find the more kids get exposed to numbers over 100 the better they are in that 100-120 range.  If kids can do the numbers between 100 and 120 than they certainly can do the numbers up to 200.
I once more asked if there were enough for everyone to take 10.  They agreed there was and each took 10 more.

We again counted by 10's (OVER 100!!!)

Our pile in the center of the table was getting quite small.  I asked kids if there was enough for everyone to take 10 more and they were sure there were not.  I asked for ideas about how many more they could each take.  After some discussion, we came to an agreement that 5 more would work.

There were a few left in the center of the table. So we arranged them in a group of 10 as well.  The kids were having a tricky time figuring out how many altogether so we decided to push the groups of 5 into groups of 10.

 Here is a final shot of what the table looked like when we were finished.  We counted them all by 10's and then had 1 left over.
We wrote our final number and were out of time so we did a quick clean up and will continue working on these ideas as the year goes on.

How do you work on counting and estimating in your classroom?