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Estimation Jar

Compiled By: Editor

Fun ideas for teaching estimation skills to students and encouraging thinking not guessing.

Posted by: Tracy

I found this idea, I think on line awaile ago, and began using it this year. I have a see through plastic jar that I send home every week with a different child to fill up with objects of their choice(pasta, cereal, sunflower seeds, etc). They get very creative. The class must guess how many are in the jar. Only the student who filled up the jar knows. I guess also. On day one, I let them record their responses on post its and place them on the chart paper. With the jar I purchased, there is a smaller jar. On day two, I take out enough of the objects to fill up the smaller jar and let them know how many are in there. This gives them an idea as to how much could possibly be in the bigger jar. It allows them to get closer to the estimation (sometimes). If they want they change their answer. (once they get the hang of it I will eliminate this step). On day three, we use the estimations to cover other skills we've learned (graphing, average, fractions, etc.)
On day four, we count the contents and see who is closest, within reason. I usually award a small prize (pencil, extra stickers, etc.) It gives me an idea as to who is good at estimation and those that are not, who will get better after a few tries. I also drew lines on the jar to show 1/4, 1/2, 3/4 and inform the child that if they use small abjects, such as rice, on fill it up to the 1/4 or 1/2 mark. It helps with fractions when we estimate. As I write this I just thought that maybe I can have the children write their own word problems based around estimation. I hope you understand what I mean. If not just respond to this post.

Posted by: LindaR

Estimate accurately? Not sure I understand... I thought that having estimation skills allowed students the ability to reason through math answers.

For example, you could display 4 quarters and then ask the children if you would have enough to purchase a CD that costs $1.25. Estimate first --yes or no. Ask why...then calculate answer to see if correct.

Estimating is also an important science process fact, we estimate with MANY things in life. You could have the children brainstorm things they could estimate and what answer are they seeking (how long, how heavy, etc.).

Have them create their own estimation activity (drawing and question), and then create a class book whereby you work on the questions daily.

You could have your own challenges in a daily estimation activity: Everyday have something in the classroom that the children need to estimate (length of chalk, your pencil).

They need to write down their guess and what kind of measurement (rulers, paper clips, craft sticks, etc.) they would use to know for sure.

This can be recorded either in their journals or submitted on a card (will there be some kind of prize for correct guessing?)

At the end of the day (or whenever you choose), read responses.

Estimation can be extended to many things....make graphs!

Hope this helps! I look forward to seeing more ideas....Have you checked the PT archives? Great place!

Estimation Jar Too
Posted by: BelleBelle

I also use an estimation jar in my classroom to reinforce and master maximum, mimimum, range, median, and mode.

Every Friday I pass out a post-it to each student. One student walks around with the jar and allows students to glance at it without touching. Then once they have decided on an estimation they write it down (along with their name) then I have call students to go up to the dry erase board and stick their estimation post-it up. The students must put their estimation in correct number order independently (this is another mastery standard).

Once all estimations are in, the student who walked around with the jar gets to dump the jar and everyone counts the items in the jars by 5's, 2's, 3's. It is such an great way to practice counting by different numbers. Very repetative. Then as a class we see who was closest and that person gets to take home the jar to fill with items of their choice. We then take all the data and identify maximum, mimimum, range, median, and mode. After that we create a bar graph with the estimations.

The students love the activity, it helps to reinforce the skill on a weekly basis and allows the students to enjoy learning.

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estimation station
Posted by: Trish

I have done an "estimation station" for the past six years. I assign students a week to bring in their estimation can be treats or objects (such as buttons). The students are required to put in one guess by Friday at 12:00. The person who brought in the treat and a friend gets to figure out who the winner is (the person who guesses the closest without going over). We do a big drum roll then say who the winner is. The winner has to help figure out how many pieces each person gets with the winner getting the most (I help them figure it out on the board with all of the other students giving input).
I do tell parents that I prefer the treats be wrapped. I have the parents count how many objects there are and put the answer in a sealed envelope.
The students love this and it is a special treat each Friday. Of course,there is always a family who can not or does not want to bring it in....that is fine...I just bring it in that week or we don't have an estimation station that week.
Hope this helps!

Estimation jar
Posted by: Wendy

I used the estimation jar last year with students and I found it helpful if students filled the jar weekly. Every Friday, students would guess how many items were in the Estimation Jar. The student who came the closest won a prize (lollipop). Then I would them pick a popicle stick (out of a small can; everyone had a popicle stick) and ask that person if they would fill the estimation jar for the next week (I would send home a paper explaining when to return). I would return the contents of the Estimation Jar back to the "filler" and ask them if they would like to share with the class. I thought this worked because it rewarded those who had the closest estimation and give everyone a chance to fill the estimation jar. Good luck; Wendu

Estimation Station
Posted by: Cathy

I also use an estimation jar (It is part of my math center) and instead of having the kids just guess how many items are in the jar I also have them write why/how they came up with that number. I change the size/shape of the jars I use and I also use different size items. This keeps the kids from coming up with just a wild guess and allows them to really think about their estimation. I've had kids come up with some really great explanations. One time I used a jar with flat sides and one student explained how they counted up the total on one side and multiplied that by 5 (one for each side and extra for the core of the jar) I give a small prize to the best estimation (they have to come close to the total but also have a good explanation) and the whole class splits what is in the jar.

teaching estimation to first graders
Posted by: Laura White

This is a fun estimation activity I like to do around Easter time. Make a large easter egg out of poster board. Ahead of time, count out how many mini-marshmallows it will take to fill the egg. This is so you know the correct answer ahead of time. Show the students the egg and some marshmallows. The students each write on a cut out egg their estimation of how many marshmallows it will take to fill the egg. Then glue the individual eggs all to a large piece of paper. Now,from your marshmallows that you have already counted, give each child a small handful. They are to count them in groups of tens and ones. The tens should be in a pile and the ones should each be by themself. Then exchange their marshmallow number for unifix cubes. For example if they had two tens and one (1) in marshmallows, then they would go get two tens and one (1) of unifix cubes. While they are counting cubes, lay your large egg on newspaper and put Elmer's glue all over it. Students then bring their marshmallows back to the egg and they glue them down. You will then be able to count the unifix cubes to see exactly how many marshmallows were needed. Count the unifix cubes in sticks of ten. Have fun and e-mail me if I was not clear about something. Laura

Posted by: Cathy-Dee

An activity I often use to teach estimation is to have a number of small zip lock bags that are numbered. In each bag is a number of items (I start first with up to 25 items in each bag and then increase numbers later when we are learning about larger numbers).

I have enough bags for each student to have 1 bag plus at least 10 extra bags. Then I have a sheet of paper where they write their estimates. They must first guess or estimate their answer and write it with a coloured pencil. Then they can open the bag and count the object and write the actual count.

You have to really watch them during this activity, because first graders hate to guess - they want to change their answer because they feel that guesses are wrong. I always emphasize that a guess is always right, but some guesses are closer to the actual count than others and as we practice we should be able to have our estimates closer to the actual count.

I demonstrate first with a couple of sample bags and show them how to write their guesses and actual counts as well as the number on their bag on their recording sheet. I also let them know they probably will not be able to do every bag today, but that they should try to get 5 bags finished. I have also precounted all the bags and have the answer key. I don't worry when marking if the actual counts are correct as long as they are quite close. Sometimes when the bags are being used by a number of students one or two items will fall out.

Hope this helps, feel free to email me if I wasn't clear or if you have any questions.

Estimation and Patterning 2nd Grade
Posted by: Sandy

Estimation--Every ten days, we have "Pocket Day" in my classroom...we've done it since the beginning of the year, but you could introduce it at any time. I put out a tub of unifix cubes and a clear gallon jar in the morning...the kids will come up and put as many unifix cubes in the jar as they have pockets that day. Then, during math, we estimate how many cubes are in the jar, and we fill in a chart that lists number of pockets and how many had that number...

0 pockets 4kids 0 pockets total
1 pocket 2kids 2 pockets total
2 pockets 5 kids 10 pockets total

We go up to 15 pockets, then we work on our total number of pockets. Choose one kids to count the unifix cubes, while the rest add the totals together to find your grand total. Let a few kids share what they think the grand total is, then you solve it by modeling adding tens, ones, etc...and check against the unifix cubes. My kids love doing this activity and it keeps them very involved!

book on estimation
Posted by: Margaret

Stuart Murphy has written a children's book on estimation named "Betcha'" I have used it for about 3 years to introduce estimation to my class, and it does so wonderfully. I have seen its value when my students estimate, because I have slips of paper for them to write their name, their estimate, and how they arrived at the estimate. Many times I see ideas from the book used as part of their explanation. Stuart Murphy has a series of books on different math strands that are all VERY good to use to introduce your topic with.

Estimation Station (ongoing)
Posted by: Krissy

Something fun I did for my students last year was have an "Estimation Station." I did this every Thursday morning and when students came in the room, there was something new for them to estimate. We did things like:

*raisins in a box
*marbles in a jar
*the length of my foot in inches
*the length of the classroom in meters
*how many large marshmallows would fit in a jar
*how many pennies were in a jar
*a catalog page with items circled to to add up and estimate total cost

They enjoyed having a new task every week and it really gave them a good idea of what it means to estimate.

Estimation Jar
Posted by: Joy

Check your local dollar store for neat items to add to your estimation jar. Many of the items can be used again as manipulatives or in centers.

rainbow jems
black stones
very small rainbow craft sticks
small plastic toys
colorful erasers
plastic coins
mini sponge animals

I hope these ideas help a little! I love the estimation jar!

estimation jar
Posted by: Joanne/2nd/TX

We decided to do an estimation jar each month in our learning centers. We chose things to go along with the holidays, etc. Aug: sunflower seeds, Sept. M & M's, Oct. Popcorn, Nov. candy corn, Dec. Peppermints or candy canes, Jan. mini marshmellows, Feb. hearts, Mar. Lucky Charms, Apr. jellybeans, May goldfish or Trix cereal. I think we decided to share the candy with the class and give a pencil or a prize to the winner (s). We also planned on doing some graphing with this activity.

estimation jar
Posted by: Ramie

I used an estimation jar every week last year. I started the year with big items like tennis balls and pairs of socks. As the year moved along the items got smaller. Some other ideas are wads of paper, golf balls, unifix cubes, or wash cloths. I even sent the jar (mine was pastic) home over the weekend with a student to fill. They loved being the only one who knew the total.

estimation activities
Posted by: abby

Here are some more ideas to encourage thinking rather than guessing:

Place 10 (or 25 items) in a small jar and tell the class how many you've put in. The class can observe how much room that takes up in the jar. Using that information have them estimate how many items it would take to fill the jar.


Fill a jar 1/2, or 1/3, or 1/4 full. Class estimates number then counts to verify. Class can then estimate number in totally filled jar.

Estimate number of pennies in a jar. Once class has answer, estimate if number of nickels to fill jar would be more or less. Tell why.

Other things can be estimated such as length (how many paper clips will fit across width of paper, length of paper, length of desk etc.)

How many steps across the room? to the bathroom? to the gym? to the office or cafeteria?

Time: how many seconds/minutes to walk to destination in building, how long to do 10 jumping jacks, 20 jumping jacks?
How long does it take to say the pledge? sing a song?

Weight: if you have access to scales

Have fun with it. I agree with previous poster. Remember to encourage "educated, thoughtful" guesses.