Making Your Estimation Jar COUNT!

Hello!


I know it’s been a LOOOOOONG time since I’ve blogged.  Life has just gotten in the way.

I want to share with you how in less than five minutes a day, I make the most of an estimation jar in my classroom. This is a rather long post because I have a lot to share about this...

First of all, we use a recycled plastic jar.  I’ve found mayonnaise jars and the jars that peanut butter pretzels (yum) come in work well.  I always keep extras on hand in case we need a replacement.  I put a label on the front that says, “2-C Estimation Jar.”  I put packing tape over the label to keep the label as protected as possible.

 

Next, I make a simple chart on poster board with all the students’ names.  I always leave extra space for move-ins.  I laminate the chart because the students will write their daily estimates with vis-à-vis pens so the board erasers can wash them off each day.

I use a pocket chart to display our cards for the week.  I also have a class set of explanation letters run off. (You can grab a copy here.) I keep the letters on a clipboard under a checklist on which I will keep track of who has the jar each night.

Now, we’re ready to get started!

On our first day of estimating, I put items in the jar for the students to estimate.  After that, they take turns bringing in the jar with items they have counted.  The student tapes his answer facing the bottom of the lid or gives me a slip of paper with the answer when she arrives.  The person with the jar places it in the estimation area before taking his seat. Students write their estimates on the chart behind their names using vis-à-vis markers during our morning business time.

During our math meeting/calendar time, we will spend 3-4 minutes doing our estimation work.  I always model estimating and make my own guess orally.  I model thinking in terms of how many groups of ten I believe the items could be separated into.  I also compare the items in the jar to previous items we have had, encouraging the boys and girls to use previous knowledge and comparison skills.  I point out that good estimating requires strategic thinking to make the best guess possible.

After I tell my estimate, I will have the class guide me in making our sentence strip card for the item. 

Our discussion generally goes like this…

I will write the name of the child who brought the jar.  I ask the class why I am using a capital letter.  They will tell me it’s a proper noun. I ask the boys and girls how I will show that the item belongs to this person.  They tell me I need an apostrophe because the word is possessive. 

Then we’ll discuss how to write the name of the item.  We will clap and stretch the word to come up with the spelling for the singular form of the word. This reinforces our phonics skills and allows me to model spelling strategies.  Sometimes, we “have-a-go” with the spelling.  We do this by writing all of the possible spellings of the word to decide which possible form looks right.  Sometimes the spelling is on the item; I’ll point out that we have a resource to use.  Other times, we’ll look in the dictionary.  Often the items in the jar will be a product that we can write as a proper noun.

Another math/language skill that we often have the opportunity to practice with our jar is coming up with a common term for the items in the jar.  An example would be if the jar is filled with pennies, nickels, dimes and quarters; we can use the common term coins.  This provides vocabulary development and carries over into fraction work.

Once we have the base word, we’ll determine what we need to do to make the word plural.  Again, we’re practicing our language skills!

As we are making our sentence strip, the student who brought the jar is getting place value blocks and place value strips ready to display.  I will SLOWLY write the number for the estimate on our recording card.  The kids LOVE this part, seeing how close they are!

Of course the very next thing we do is determine whose guess is closest.  We’ll find the two estimates the actual number is between.  Then we will mentally add or subtract (early in the year I have to help or model this) to decide which estimate is closest.  This student takes the jar home unless s/he has had a turn in the current round, in that case s/he gets to pick someone who needs a turn. If we have a tie, the kids will guess a number between one and one hundred to see who can get closest to a number I’ve written down (another math practice opportunity).

The next thing we do is put the sentence strip in our pocket chart.  We always arrange the strips in order from greatest to least, allowing us to compare numbers.

Now we will have the student who brought the jar show us the number using place value blocks.  We count as s/he drops the blocks into a baggy we have on the board.  This gives us a chance to talk about hundreds, tens, and ones, even thousands occasionally. The student then shares the place value strips needed to make his/her number.  We look at the number with the cards separated and overlapped.  (These place value strips are awesome; there is so much you can do with them!) 

 

These estimation jar activities have really enhanced my students’ number sense, problem solving ability, and language skills.  I feel that these few minutes are very well spent and wanted to share what we do with our jar in case you would like to try some of these things yourself.

Happy Teaching!

Credits: Squiggly Frames    Jar   Frame on Letter