In the year 2015, Pi Day will have special significance on 3/14/15 at 9:26:53 a.m. and p.m., with the date and time representing the first 10 digits of Pi. That same second will also contain a precise instant corresponding to all of the digits of π. However, some argue that 9:26:54 a.m. and p.m. on 3/14/15 are more accurate because of the 11th digit of π being 5, which would cause the 10th digit to round up to 4.
In mathematics, an irrational number is any real number that cannot be expressed as a ratio of integers. To those who haven't had higher mathematics, it means that, so far, nobody has found the point where the numbers might start repeating as in the fraction 1/3 = 0.3333333 forever.
In the 20th and 21st centuries, mathematicians and computer scientists discovered new approaches that, when combined with increasing computational power, extended the decimal representation of Pi to, as of late 2013, over 13.3 trillion digits.
The closest easy-to-remember fraction for Pi is 22/7.