One of the best Halloween math activities to teach in an 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!
Halloween Pumpkin Math
There’s a lot of math that can be practiced in this activity: estimation, skip counting, measurement and subtraction.
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 down load a free pumpkin-math-printable here. Younger students can complete the activity verbally, there’s a lot of learning just in the doing! 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!
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