Today's estimating and counting routine was done with students who are about 1 month into grade 3. This is also an excellent routine do with kids from K up to grade 4. The strategies and efficiency will vary greatly among the grades but there is something different you can bring to each level.
This routine was not done as a whole group lesson but rather in small groups of 2-3 students. I gave each students a scoop of dominoes and asked them to spread them out on the table in front of them with the dot side up. I gave them about 15 seconds to look at the dominoes and come up with an estimate about how many dots they think are there. Then one person in the group covered the dominoes with a student sized white board and each person wrote down their estimate.
|The dominoes awaiting estimation|
|A group of students record their estimates|
Once students were done estimating, their job was to figure out how many dots there actually were. I did not provide parameters about how this had to be done or make suggestions about ways to do it efficiently. It was late on a Friday afternoon however, and they knew if they had any time left before end of the day pick up, they got to play with the dominoes so they were super motivated to do this task efficiently.
Here is a look at some of their strategies.
|This group started by putting some dominoes together to make 10's but had more that could not make a friendly ten and they did not think about going farther and trying to make 20 or imagine moving dots to make tens. They pulled out the 100 bead strings to help them when they got stuck adding unfriendly numbers.|
I closed this session by having each team share their strategy for figuring out how many dots and telling how well their strategy worked and if they thought it was an efficient way to do it. I am always amazed at how perceptive kids are about their own struggles and successes.
Want to make sure you see part 4? Check the upper right hand corner of this page for ways to follow my blog so you will always stay informed!
What is your favorite math manipulative to use for estimating? Respond in the comments below!