Show Me Your Pi!


March 14th is Pi Day and I wanna do a thing. I want to teach our kids what Pi actually means.

Pi (π)…you know that thing kids proudly memorize as being approximately 3.14 or 22/7. I betcha though, if I asked most kids what pi actually represents, I think the majority wouldn’t know. So let’s teach it to them in a hands-on, fun, and memorable way.

Here’s what we did at our house…

Your Mission, if you choose to accept it: Make a Pie.

Any pie: apple, cherry, pumpkin, sweet potato,…ummmm chocolate pecan pie…(sorry I got carried away in my thoughts there for a moment)…key lime, lemon meringue, peach…even a pizza pie will do. You choose. Store bought pies or pizza delivery will also work just fine…I won’t tell anyone!

Circumference and Diameter

Once your pies are ready, have your kiddos do two things: take the circumference and the diameter of the pie. Let’s break these terms down:

  • Circumference – the distance around the outside of the pie
  • Diameter – the distance across the middle of the pie (at its widest point)

Finding Pi

Since our pies are circles, it’s probably easiest to use a piece of string to measure the circumference.

  1. Measure – Have your student place the string at a starting point on the outside of the crust, and then wrap it around the outside of the pie. Mark it and measure the length of the string. Now, have your student measure the diameter by placing the string on one side of the pie and go directly across the middle of the pie. Mark it and measure it.
  2. Divide – Here’s the formula: Circumference ÷ Diameter. If you’re using a calculator, type in the circumference, hit the division sign, type in the diameter, and hit the equal sign. If you’re doing the work on paper (yeah for you!), remember circumference is the dividend, so we put it in the inside of the division sign.
  3. Find Pi – Voila, your answer should be somewhat close to 3.14159265359 or 3.14 for short. (It may not be this number exactly as we have to account for a little human error in measuring, but your number should be in the vicinity.)

Want to make it even cooler? Make two pies of different sizes. You’ll get to see how that ratio of circumference to diameter is the same no matter the size of your pie. Who said math can’t be cool?!

Want to get fancy? You can go a step further and learn how to use pi to find the area of a circle.

I will create a post on the Nicole the Math Lady Facebook Group. (If you’re not part of our closed FB group for NTML members, click on the link at the bottom of your email to request permission to join.) Post your photos/videos of your pies there. Help me create a little army of junior mathematicians who really understand pi. Can’t wait to hear how all about it!



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    1. My 5/4 student loves the rare days we use baking for math. Maybe we will make the whole day Pi day and I will let her take charge of doing the math to double our recipe, complete the Pi activity, and call it a day. Thanks for the fun inspiration!

      PS, my own Nicole loves her math now that we found your website. She always asks to do extra now!

  1. I am drooling think of all the pies we HAVE to make. Best assignment for math EVER! We can’t wait. Coconut cream, chocolate cream, sweetheart cherry pie, I could keep going. 😋

      1. i love coconut cream so much🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳🥳

  2. This is such a fun and awesome idea!!! The kids will love it!! We are not on social media. Is there an email address where I could send a picture? Thanks for such a fun idea!!

  3. Well you asked the right person! I have 3 kids in your program and own a pie bakery as well. Farmhouse Pies in Bend, OR will be making some fun Pi Day pies and will post to the FB group!

  4. Great ideas! My high-hopes want to make pizza-pi for lunch, chicken pot pie for dinner, and chocolate pu for dessert! 😋

    1. Circumference lessons start in the 7/6 textbook. You can use the magnifying glass to search circumference and you will see the appropriate video for your age level. I also posted a short video on FB yesterday that shows what to measure (it’s not really a lesson but the students can see what I’m talking about.) Have fun!

  5. We are celebrating an early Pi day on Saturday because our co-op meets Monday.
    We did pi day last year too! We had the cousins over and did a pi themed pot luck.
    We had pizza pie, Sheppards pie, chicken pie, and of course a few dessert pies.
    The catch…. the kids couldn’t have any of the dessert pie until they solved some pi related problems.

  6. Hi I have a niece and math is tough for her but if you can help me make it understanding for her I would love it
    My name is William but they call me K.V

  7. I watched this and want to do this next year.

    This video showed me CIRCUMFRENCE and DIAMETER. Even though I haven’t learned them in math yet, I understand them completely

  8. I was not able to make a pie for I did not see this until after March 14! I was really bummed out! I did just want to note that the pie on the cover of this section looks absolutely amazing!!!!!!!