Pumpkin Math

How Many Seeds in a Pumpkin?

Post Written and Created by Math Maniac

This story is about a group of kids who are asked by their teacher to figure out how many seeds are in 3 different pumpkins. They talk about the size of the pumpkins, estimating and counting ideas. Some kids count by 2's some by 5's and some group the seeds into piles of 10. There is also some great information in this story about how to estimate how many seeds a pumpkin has just by looking at the outside.

I love this lesson because it combines my love of math literature with counting and estimating routines. I began this lesson by presenting my students with 2 pumpkins. I did this lesson with second graders but it would work with other kids K-3 with some small adaptations. One was a very small Jack be Little pumpkin and the other was a larger pie pumpkin. I asked them to estimate which one had more seeds. Everyone was convinced that the larger pumpkin would have a lot more seeds. We made some estimates but they were really all over the place ranging from 17-1000.




Next we cut the pumpkins in half and adjusted our estimates based on what we saw. The estimates for the smaller pumpkin ranged from 80-200 and the estimates for the larger pumpkin ranged from 101-320.


The inside of the larger pumpkin



Inside of the smaller pumpkin

Kids worked in small groups and got all the seeds separated from the other guts. When I do this lesson again, I will be sure to have more pumpkins because despite this being a smaller group of students, there were to many kids working on each pumpkin. I would recommend no more than 4-5 kids per pumpkin for optimum working conditions. Kids continued to adjust and refine their estimates as they put the seeds all in one place. It was obvious to all students that there were more seeds in the large pumpkin than the smaller one.


After a quick rinse of the seeds, the groups counted them mostly grouping into 10's. We came to the conclusion that the small pumpkin had 134 seeds and the large one had 285. We spent some time comparing these numbers and wiring them in different ways. We finished up the lesson by reading the book. It was interesting for kids to compare their own experience with counting the seeds to the experience of the kids in the book.

This was a fun fall lesson and definitely one I will be doing in the future! There are a lot of grade levels that I could apply this lesson with.