pi day, what is pi?, what is the number pi?, books on pi for kids, the golden rule and pi

Pi Day!

What is Pi?

Today is Pi day!

Get it?

3.14. March 14th. 3/14.

Yes, a math joke!

I wanted to celebrate Pi day by showing the relationship of math to the world around us including circles, pyramids and great works of art!

pi, pi day, pi phi and fibonacci numbers

p.s. I have a post on the math of spirals if you want more math in nature.

Pi is a name given to the ratio of the circumference of a circle to the diameter. That means, for any circle, you can divide the circumference (the distance around the circle) by the diameter and always get exactly the same number. It doesn’t matter how big or small the circle is, Pi remains the same. Pi is often written using the symbol  and is pronounced “pie”, just like the dessert. from Math.com


Another way to think of Pi. You can measure Pi by constructing a physical wheel and rolling it out.

Take a circle whose diameter (all the way across) is 1. If you roll it until you get back to the start, it will measure out Pi units. (Image from Wikipedia)


Pi and Phi in The Great Pyramid of Egypt

pi and phi in the Great Pyramid of Egypt

There is compelling evidence that the design of the pyramid embodied these foundations of mathematics and geometry:

  • Phi, the Golden Ratio that appears throughout nature.
  • Pi, the circumference of a circle in relation to its diameter.
  • The Pythagorean Theorem – Credited by tradition to mathematician Pythagoras (about 570 – 495 BC), which can be expressed as a² + b² = c².

Image and information from The Golden Number.


And it turns out that Phi (Φ) and pi (Π) and Fibonacci numbers can be related in several ways!

Artchoo! shows the connection between Phi and art with her post on the Golden Ratio for Kids:

Many artists have subsequently taken this idea and used it to plan their painting compositions. Leonardo DaVinci was probably the most famous artist to use the Golden Ratio in his paintings. Georges Seurat also used it. Check out the Mona Lisa, Bathers at Asnieres, and the Last Supper. from Artchoo!

pi in art, Pi day and art, math and art, ArtchooImage from Artchoo!

Chapter Book for Pi Day

Clare Vanderpool’s Navigating Early is the perfect chapter book for kids to celebrate Pi day. Here’s why from 100 Scope Notes:

It’s 1945 and Jack Baker is not in Kansas anymore. He’s in Maine, sent to boarding school after the death of his mother. It’s an adjustment. Things are different, but nothing is as different as Early Auden, an outcast savant obsessed with his brother, thought killed in WWII, and the number pi. He sees an elaborate story of Pi in the endless chain of digits. When Early sets out on a quest to find Pi by tracking a legendary black bear on the Appalachian Trail, Jack joins him. Their quest brings them into contact with a cast of memorable characters and unexpected, sometimes threatening situations, Early’s story of Pi begins to reflect reality. We soon realize that Early and Jack are each searching for something. While not exactly what they bargained for, both find what they seek. from 100 Scope Notes

Clare won the Newbery Award for her first novel, Moon Over Manifest, and her second book does not disappoint!

 Click on image to view at Amazon or here for Barnes and Noble.

pi day, what is pi?, what is the number pi?, books on pi for kids, the golden rule and pi

By Mia Wenjen, PragmaticMom


  1. Alexandra

    Both my parents are mathematicians so I was “lucky” to hear maths jokes all the time! 🙂
    Alexandra recently posted…An amazing app – Kids’ Vocab from MindSnacksMy Profile

  2. omgosh lady! where were you when i needed to explain this to the teens how many years ago?
    to be frank, i never totally got it myself until now, so thank you. one day the preschoolers will say “wow mom you’re super smart” and i’ll pretend i just know this stuff, that i didn’t learn it from you.
    (i’ve always been more interested in the other pie)
    vanita recently posted…Bounce Rate Defined Series: Wrap Your Blog In HoneyMy Profile

    • Hi Vanita,
      My dad was a math professor and I am still confused about Pi. I had to look it up too! I only vaguely remembered that it was related to a circle somehow … Thank goodness for Pi Day as a motivator!

      I’m more interested in the other pie too!
      Pragmatic Mom recently posted…Pi Day!My Profile

  3. Hooray for Pi Day! We have done a bunch of Pi Art activities. But real life intervened and I never got the blog post written. Boo.

    • Hi Mom and Kiddo,
      Please share your Pi Art activities on your blog at some point! We never do anything to celebrate Pi Day though I am thinking that eating pie would be fun! And pies ARE shaped in a circle!!
      Pragmatic Mom recently posted…Pi Day!My Profile

  4. I need to do something for pi day with my kids this year – I think they are old enough to enjoy it!
    maryanne recently posted…Favorite Windows Phone Apps and Games #MeetYoursMy Profile

  5. Loved your post and the many ideas for many different ages. I used to love celebrating Pi day in my teaching days.

  6. That was a good reminder (Pi). It has taken me back to those days – I never liked maths in school. How I wish I could have paid more attention to my maths teacher.
    Viren recently posted…Email Marketing to College StudentsMy Profile

  7. Asianmommy

    Wow–I never realized the Golden ratio was used in artwork like that–very cool!
    Asianmommy recently posted…The Epic Adventures of Princess MoonfaceMy Profile

  8. Jeanette Nyberg

    I can’t believe we didn’t eat pie yesterday! Thanks for the mention, and I will just never get over how awesome this whole concept is.
    Jeanette Nyberg recently posted…On the Go! Travel Activities for KidsMy Profile

  9. tricia

    Pragmatic Mom- I missed writing about Pi Day, but I can’t wait to write about Phi Day which I plan to unofficially decree as January 6th…with January 6, 2018 being the year to look forward to complete the decimalization of 1.618. 🙂 When I write about my favorite ratio, I will be sure to reference this post and the one you wrote about spirals in Nature….My kids are 4 and 5 and they already know the difference between the archimedian spiral and the logarithmic spiral (my favorite shape in the whole universe). 🙂
    tricia recently posted…Why Rollerblades And Training Wheels Do Not MixMy Profile

  10. Ann

    Pi day = great idea! Love the animation and great idea from Artchoo to each pie!
    Ann recently posted…Inspiration for the BunnyMy Profile

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