School Supply Estimation Jars

I was a total bookworm when I was a kid. I was the little girl who took books to the beach and read my summer vacation away. I had an insatiable appetite for all things written- books, magazines, cereal boxes, etc. You know what I didn’t like, though? Numbers. Numbers were far too cut and dry. There was no room for interpretation, imagination, or creativity. I felt boxed in by mathematical rigidity and didn’t like that one bit. But in fifth grade there was one math activity my teacher offered us that I loved- the estimation jar. Every week my teacher had a jar filled with various treats, supplies, or knick knacks. During our free time students were allowed to go to the jar- hold it, turn it, and investigate it- to estimate how many objects it held. It felt like mathematical freedom…in a jar 😉 Nobody told me how I had to solve the problem, I had the freedom to test out my own strategies. And throughout the year I did just that, I tried many different methods and looked forward to each week when I got to try it again. I loved that estimation jar!

Now that I home preschool my kids, I’ve thought back on all the things that I loved in school and the estimation jar was at the top of my list. I wanted to find a way to bring my beloved estimation jar down to a preschool level.

Making an Estimation Jar for Preschoolers

Since I was re-interpeting the estimation jar for kids that can barely count to 20, I knew I couldn’t really have more than 20 items in the jars (I cheated with the dice and ended up using 24). I used something we have an abundance of- school supplies! (back to school sales have been good to us 😉 ) Here’s some supplies you might consider using:

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• Small mason jars
• Pencils, crayons, Pip Squeak markers
• Pencil top erasers
• Alphabet beads

I made three jars- two mason jars with pink pearl erasers and dice and a long jar with pencils. I had to get creative for the pencils, so I used a straws container that I found in the Target Dollar Spot wrapped with painter’s tape.

My four year old had fun trying to count each item in the jar. I explained to him that we were going to estimate the number of items, then open the jar to count them afterwards (if your kids have a hard time understanding how to make an estimate, guide them by asking questions like “do you think it has more than ten” Less than twenty” “why?”)

It was fun to listen to my preschooler’s reasoning skills! He changed his estimates approximately 14,000 times, but it was fun nonetheless 🙂

When it came to counting the items, he was really orderly about the process!

And we used our tally mark method to practice counting the pencils (see how we tally mark with pencils here).

All in all, our back-to-school estimation jars were fun and a great way to practice counting and developing number sense. What will you fill your estimation jars with? Show me your versions of this activity on Instagram!