Our Estimation Jar


Every week in our class we practice the skill of estimation using our class estimation jar. This is how we do it.

First, we look at the items in the estimation jar. Last week it was filled with glittery pompoms. We each estimate how many things are in the jar and write our estimates on a sticky note.

Then we take our sticky notes and  put them on a number line so we can see the range of our estimates. Last week, the range of our estimates went from a low of 52 to a high of 10,000 pompoms! As we practice and learn more estimation skills, we expect our range will get smaller.

We graph our estimates in our Class Estimation Book. These copies came from Creative Mathematics.

Then our counting committee counts the items and we see how close our estimates were. Last week there were 200 pompoms in the jar. Two people guessed that number exactly! We record our actual answer on our estimation jar poster.

This week our jar is filled with Unifix cubes.

How many cubes do you think are in the jar?

What else should we put in our estimation jar?


  1. Dear Mrs. Hamman’s Class,

    We think you should try sea shells in your next estimation jar. We tried it the first week of school and had an actual number of 54 shells. This week we are also doing cubes. The only difference is we had to use a tub instead of a jar.

    We think there are at least a hundred cubes in your jar. Please keep us posted after you discover the actual amount.

    We noticed you have an estimation range poster. How does it work? Should we be using one in our classroom?

    Your new friends,

    Mrs. Moore’s Class

    • Dear Mrs. Moore’s Class,
      Thank you for your comment! We like your blog. The range poster helps us see our estimates in order. We counted our cubes and there are 168. How many did you have?
      Your new friends,
      Mrs. Hamman’s Class

  2. Hey I like your maths stratiges.We use connect blocks to do our maths that we think is very difficult.Do you think maths is simple or difficult?

  3. hi i like your vidio of the kites it looks like fun i wish we did that
    was it fun getting to fly the kites?
    jack room12

  4. Dear Mrs. Hamman’s Class,

    Thank you for your reply. We ended up with 288 cubes in our tub! We had a very big range this week. We think it might be because we used a tub. Our teacher said she will make us a estimation range chart so we can see our range better.

    This week we estimated dinosaurs! We are getting ready to check our jar as soon as we are done with this comment. What are you using this week?

    Please keep in touch,

    Mrs. Moore’s Class

  5. Pingback: The Oreo Project | Mrs. Hamman's Class Blog

  6. I have a bunch of estimation jars in my class if you would like to use them.

Leave a Reply

Required fields are marked *.

Skip to toolbar