BY RYAN E. SMITH

BLADE STAFF WRITER

 

Dan Hellerich has a favorite number, but he can't tell you what it is.

 

It would take too long.

 

He tried before - in college, with the help of some fellow students - but after "a good hour and a half or so" they had only begun to recite the digits that make up the never-ending mathematical constant, pi.

 

"I took a five-minute block of just reading the numbers," the Web developer from Minneapolis said. "I have a million [digits] on my Web site."

 

Even if he can't say it, he can celebrate it. And there's no better day than today - Pi Day. (After all, it is March 14, or 3/14.)

 

 

It's unclear when Pi Day was first celebrated, but the truth is, pi has fascinated people for ages. While its value often is reduced to 3.14, it continues on forever with no discernible pattern. Evidence of its calculations goes back to ancient times.

 

It's a simple idea: Pi is the ratio of the circumference of a circle to its diameter. It's used in calculating all kinds of things, including the area of a circle.

 

 

 

Chao Lu, of China, holds the world record for reciting pi from memory - to 67,890 places. The chemistry student's attempt in 2005 took a little more than 24 hours and occurred after four years of practice, according to Guinness World Records.

 

For those who are satisfied with knowing fewer of the digits, there are always clever song parodies to help you remember.

 

Colleen Dezsi, a pre-algebra teacher at DeVeaux Junior High School in West Toledo, helped write one to "867-5309/Jenny," the '80s song by Tommy Tutone, replacing the phone number in the song with the digits of pi.

 

"I've been teaching it in my math class," she said. "I get my air guitar going."

 

To celebrate Pi Day today (which also happens to be Albert Einstein's birthday), some eighth grade students at the school will get to buy pies and throw them at teachers and administrators, with proceeds going to charity. They will make necklaces that require them to know the digits of pi, and they will write stories about "Sir Cumference."

 

At Leverette Junior High School in North Toledo, students will celebrate by participating in a pie-eating contest and throwing pies at the principal and other administrators. To watch or take part, the youngsters must have completed math assignments related to circles and using pi in equations.

 

The result was that kids actually were excited to do a math assignment, said Laurie Kruszynski, peer math coach at the school who helped organize the activities.

 

Pi's place isn't limited to school, however. It took center stage in the 1998 movie Pi. Nicollette Sheridan's character in the 1996 spoof Spy Hard was Agent 3.14. And in her song, "Pi," Kate Bush recites dozens of the constant's digits.

 

For her part, Mrs. Kruszynski has a pie - or is it pi? - plate with the number's digits inscribed around the rim.

 

"I've seen catalogs with all different kinds of pi paraphernalia, so I'm not the only one," she said.

 

Pi Day may be a made-up holiday, but the beauty and mystery that many find in the number is real. Some, like Mr. Hellerich, see in it the wonder of infinity.

 

"I like pi because it's an infinitely long number," he said. "Infinity is something that's hard to comprehend for some people."

 

It's even harder to calculate. The record for that belongs to Yasumasa Kanada at the University of Tokyo, who computed pi to 1.24 trillion decimal places.

 

Those extra decimal places are meaningless in mathematical terms, according to Neal Carothers, chairman of the mathematics and statistics department at Bowling Green State University. The exercise's usefulness lies instead in testing the accuracy of supercomputers and new algorithms.

 

Mr. Carothers said he gets numerous letters and e-mails each year from people claiming to have discovered new truths about pi.

 

"Somebody somewhere has given them the impression that there's some great puzzle to be solved ... and that fame and fortune awaits," he said. "Mathematically, whatever secrets it still holds are few and far between at this point."