Hey, teachers! It's time for Pi Day! Pi, an irrational, non-repeating, non-terminating decimal that we celebrate annually on March 14 (3.14), is a Greek letter used in math to represent the ratio between the circumference of a circle to its diameter. Ready to enjoy the world of Pi? Here are somefun ways to celebrate Pi Day and teach your students about this fascinating number:

• Digits of Pi Competition: Challenge your students to a "Digits of Pi" competition. About a week before Pi Day, give your students the first 100 digits of Pi and ask them to memorize as many of the digits as possible. On Pi Day, have a "Pi Bee" and see who can write the most digits in 1 minute. The winner gets a slice of his or her favorite pie.
• Paper Chain Competition: Have a group competition to see who can create the longest paper chain to represent the digits of Pi in 314 seconds (approximately 5 minutes). Give groups a different colored strip of construction paper for each digit 0-9 (a great task to ask a parent volunteer to prepare), stapler/tape/glue stick, and the first 100 digits of Pi. After the competition, have students measure their paper chain (the circumference) and use the circumference formula (C = Pi times diameter) to find the diameter of the circle. Regardless of the length of the chain, the ratio of the circumference to the diameter will be the same: Pi.
• Head and Arms: Have students cut a piece of yarn the length of their arm span. Tell students to wrap it around their head (forehead to back of head) and count how many times it goes around. Ask what they notice. They should see that the yarn will wrap around three times plus a little more. Have a discussion about the relationship between the length of their arm span and the measure around their head.
• Pie Measuring: Bring in or make pies. Have students use measuring tapes to measure the circumference of the pies. Use the circumference formula to find the diameter of the pie. Then eat! Another messy but fun variation: measure empty pie tins and find the diameter; then fill them with whip cream and play the "Pie in the Face" game.
• Read Aloud: Read a book in the Sir Cumference series by Cindy Neuschwander. Then, have students write their own Sir Cumference adventure story that includes what they've learned about Pi.
• Circle Measurements: Give students different circular objects and have them measure the circumference. Then have students use the circumference formula to find the diameter. Students can record their findings and see that, regardless of the object, every circular object with have the same ratio of its circumference to its diameter (Pi).

Are you ready? Dig in and have some fun with Pi Day!

Jennifer Kim is a long-time teacher, math coach, and teacher trainer. She has apassion for mathematics and is known for making the world of math come alive for students. Jenn lives in California, where she enjoys the beautiful outdoors and spending time with her family and friends.