In terms of mathematical concepts, the ratio of a circle's circumference to it's diameter is pretty straight forward—not too hard for fourth-graders to grasp.

Central School REACH instructor Jill Zimmer sees lots of valuable concepts in introducing students the mathematical magic that happens—as well as the Greek letter pi used to represent the non-ending series of numbers.

"It's the concept of infinity that's so intriguing," she said Friday, during the school's "Pi Day" for fourth-grade classes.

Pi Day is marked with several activities aimed at introducing these ideas to the young students, first with a video introduction to where the pi comes from, followed by a hands-on experiment calculating it by measuring a hula-hoop.

Zimmer pointed out the students are expected to be able to measure to within a quarter-inch at this age, so the calcualtions should come very close to the 3.14159265.... 

"It's a fun introduction to it, but when they come back to it (in later grades), it's easier to understand," Central School Principal Janet Milita said.

The school marked Pi Day Friday, instead of March 14 as it usually is celebrated, because of a conflict with the school's International Day next week.

How many decimal places can the students understand? One representation that may help is a project the students did making necklaces using different colored beads to represent each number.

They were given a sheet with pi carried out to 60 numbers as a guide...