We do this as a weekly math activity. The estimation jar comes out every Friday and the half sheet is due by the following Thursday so we can go over it on Friday. I collect a variety of containers at the dollar store, grocery store, etc. and I fill the jars with candy and small items (like erasers or toys).
I ask an Estimation Question for the jar each week. For example, one week I had plastic dinosaurs in the jar and some possible questions are: (choose only one question per week)
- What fraction of the dinosaurs are quadrupeds?
- What is the ratio of herbivores to carnivores?
- What fraction of each color of dinosaurs are in the jar?
I copy and cut the Challenge sheets and I leave them in a plastic container with the current week’s jar and question (written on a sentence strip). The student with the best sheet wins the jar and its contents each week.
I score the sheet as follows:
One point for the estimate if it is within reason.
One point for every math vocabulary word used in the description. (these can add up fast)
One to ten points (or more) for a detailed description.
One to five points (or more) for the rationale statement.
As you can see, the kids do not get a lot of points for the actual estimate, the important parts are the description and math vocabulary and the rationale!
We display “All-Star” sheets on a bulletin board in the room in order to encourage the kids to improve their descriptions and use of math vocabulary!
We make a poster of the empty jar and write in ways to describe the jar and its contents.
This pack contains:
- Student Estimation Sheets
- Jar Poster for Math Vocabulary
- Jar Poster for Estimation Jar (inside and out) Properties (shape, size, texture, color)
- Title for display and All-Star board (optional)