Halloween Pumpkin Math!

One of my favourite Halloween math activities in the outdoor classroom this time of year is pumpkin math. If you’ve grown your own pumpkins during the summer and fall in your school garden, it won’t cost you anything to dig into this hands on activity! And if you’ve got mountains of pumpkins from a visit to the pumpkin patch, or from carving jack-o-lanterns, be sure to up-cycle those squash for hours of mathematical thinking!

Related post: How to grow pumpkins with kids

Halloween Pumpkin Math

There’s a lot of math that can be practiced in this activity: for example, estimation, skip counting, measurement and subtraction to start!

To begin, talk about the concept of estimating. Reinforce that it is a reasonable guess, not a wild guess. Look at the vertical ribs along the rind of the pumpkin and have everyone make an estimate as to how many there are. Count them aloud together and record. Now work out the difference between the estimate and the actual number of ridges! This is a great time to reinforce mental math strategies to develop flexible thinking.

Next, introduce the concept of circumference (the measurement around the rind and widest part of the pumpkin). With younger students you can simply compare: is the circumference of the pumpkin greater than, or less than, your head? Students capable of using a measuring tape can estimate and measure the pumpkin circumference. I like to have kids make an estimate and then show how small 20 cm actually is. So we continue on with “it’s larger than 30cm” and “larger than 50cm”. When a child guesses a large number, say 100cm, we then look for a number smaller than 100 and larger than 50. It really is a blast, and gets everyone working with number lines!

The best part for many children is getting our hands messy, and if you are teaching in an outdoor classroom, you’ll appreciate that your classroom will be clean after this too! We have a look inside the pumpkin and estimate how many seeds are inside the pumpkin. I then give the children lots of time and space to pull out the guts of the pumpkin, separate the seeds from the pulp, and begin grouping seeds into whichever number we want to practice skip counting by. Tens are easy, but for older students I’ll work with sets of 25.

For grades 2 and up I often have students record their math on a worksheet that can be glued into their math or garden journals. You can copy or print off an example of a pumpkin-math-printable here.


Younger students can complete the activity verbally, there’s a lot of learning just in the doing! And don’t forget that chalk is a great substitute for paper worksheets. Students can record their math on the sidewalk or along a pathway by simply using chalk. If you choose to use a worksheet, students can add the printable to their  garden journals, or just add a drawing of the pumpkin, the groups of seeds or their thinking as they solve the differences in each problem posed.

Happy Halloween everyone! Have a great day with your students and get everyone outside for some fresh air!

Looking for more Fall fun in your school garden? Read my related posts here:

Fall Gardening With Kids

How To Grow Pumpkins

Pumpkin Inspired STEAM Activities

10 Best Pumpkin Life Cycle Books

If you love all things Pinterest, check out my Pumpkins and Halloween page for more festive fun and ideas:

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