If you need ideas for how to celebrate Pi Day with your students/ children, Why not pick a magical math book to share and call it a day.
Weltman has masterfully curated a collection of activities that open doors to profound and curious mathematical questions. Some of these questions are written into the text ("Did you know you can fit an infinite number of circles into a finite space?" Wait. WHAT?!), however most questions Weltman magically tucks away inside unmade art waiting to be created and discovered by the reader.
I didn't realize until researching this book that Mo Willem's Elephant and Piggie series is done, finished, finito. What?! Say it ain't so. Sorry, it is so. However, you can still get your Elephant and Piggie fix by reading Elephant & Piggie Like Reading! The Cookie Fiasco by Dan Santat. In this book within a book, Mo Willem's iconic duo make a cameo as they introduce and reflect upon Dan Santat's story The Cookie Fiasco. The Cookie Fiasco provides opportunities to explore both division and fractions.
The six recipes in this cookbook involve fractions, tessellations, circles, π, fibonacci numbers, geometric shapes, and probability. My children counted and sorted when making the Probability Trail mix. They measured and divided when calculating the ratio of the circumference to the diameter in Variable Pizza Pi and they added and counted while making their Fibonacci snack sticks. Finally, equivalent fractions were investigated a bit with Fraction chips.