Pi Day is a special celebration of the mathematical constant that is a symbol of the ratio of a circle's circumference divided by the round shape's diameter. The figure is often written as 3.14 but the number of digits to the right of the decimal point never ends. Last year's Pi Day was a big event because the date 3/14/15 matched up with the first digits of the value of pi: 3.1415. This year's Pi Day is also a special one and is being celebrated with many freebies and deals including pizza pies.  

Like Us on Facebook

Rounded Pi Day is this year's special event. In other words, when rounding the fourth digit past the decimal point the figure is 3.1416, which is the date of the celebration: March 14, 2016.

Many businesses are helping to celebrate the irrational number.

The Exploratorium in San Francisco is where the first Pi Day was commemorated almost three decades ago. This year it is offering free admission and fun activities throughout the day.

Many pizza chains are also offering deals on pies to celebrate Pi Day. Others have earlier price cuts that are still running during the special day, according to Yahoo.

The Washington D.C. area pizza chain &pizza is taking Pi Day to the next level. It is turning one location into a Vegas-style wedding chapel that will include free food, music, flowers, and marriage officer.

ThinkGeek.com is also offering a free Pi Day T-shirt. Shoppers just have to spend at least $25 in order to get the free tee.

Another reason math nerds can celebrate on March 14 is that it is also the 137th birthday of theoretical physicist Albert Einstein.

Pi was first calculated 4,000 years ago in ancient Egypt and Babylon. Archeologists have found papyrus paper and clay tablets that included the famous mathematical constant.  

Some math wizards support the use of pi while others are against it. Mathematician Carlos Castillo-Chavez explains that the figure is very powerful and is used for studying anything that cycles such as waves, and anything that recurs over and over, according to NPR.

Meanwhile, Vi Hart has a tradition of posting anti-pi videos on every Pi Day. She argues the math constant does not make sense and other ones are just as infinite as pi.

Here's an anti-pi rant: