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Pi (π) Day Activities

Pi day activities
Pi (π) Day Activities

Whether you're teaching online or looking for at-home learning ideas, we've got your number. Try these teacher-approved activities using simple household materials—no assembly needed.

Write a “π-ku”

A circumference
divide by diameter
irrational π

– Paul Doherty

More to Try

Calculate Pi

Emma Haruka Iwao (b. 1984) is a mathematician and computer scientist who broke the Guinness world record for calculating the most digits of π in 2019, and held that record until 2020. Fascinated with π since childhood, she calculated π on her computer when she was 12 years old! Inspired by her own fascination with π, Iwao and a Google team computed π to 31.4 trillion decimal places (3.14 x 1013), far more digits than the previous record. Two others (one individual and one team) beat her 2019 record, and she regained the record in 2022, calculating 100 trillion digits of pi! 

Find Your Number

Pick a number sequence that’s special to you—perhaps your birth date.

Go to the Pi-Search Page and type your sequence in the search box at the top of the page. This web site will search the first 200 million digits of π in a fraction of a second.

No result? Try another sequence. The shorter the sequence, the better the odds of finding it.

What’s Going On?

π is an irrational number, which means its digits never end and it doesn’t contain repeating sequences of any length. If π-Search didn’t find your sequence of numbers, that’s probably because the sequence occurs somewhere past the first 200 million digits. Note the qualification “probably”: Mathematicians can’t say with absolute certainty that π contains every possible finite number sequence—but they strongly suspect that it does.

As of 2019, π had been calculated to 31.4 trillion decimal places. When mathematicians study any sample of this huge number, they find that each digit, 0–9, occurs as often as any other, and that the occurrence of any digit seems unrelated to the preceding digit. This makes pi appear to be statistically random. If this statistical randomness is unending, then π must contain all finite sequences of digits, including the birth dates of everyone ever born and yet to be born. It would also contain every winning lottery number—too bad we don’t know how to identify them.