Pi(e) Day is March 14

In the classroom or the kitchen, pi(e) is a favorite!

Pi(e) Day is March 14

Math enthusiasts have turned March 14 into an informal, world-wide holiday - Pi Day - to celebrate a very special mathematical constant.

"The constant pi, denoted by the Greek letter π, is a real number for the ratio of a circle's circumference to its diameter," Jeannie Galick, Northampton Community College (NCC) professor of mathematics, explained. "We will celebrate Pi Day on March 14 (3/14) at 1:59 p.m., which uses the first five digits of the number. It is also Einstein's birthday."

In recent years, pi lovers have commemorated the day with pie-eating contests and competitions to see who can memorize the most digits in pi, an infinite number in which over one trillion digits have been calculated above the decimal point.

What makes mathematicians so excited about pi?

"We know that the approximate value of pi is 3.14," NCC Professor of Mathematics Larry Musolino said. "What is less well known is that pi shows up in some unexpected places."

Here are some fascinating spots pi can be found:

The shape of a river bending around is related to pi: if you take the length of the winding path of a river and divide this length by the distance from the source of the river to the ocean, you end up with an answer of around 3.14.

You can estimate pi by dropping a needle onto a checkerboard. Imagine you repeatedly drop a needle onto the checkerboard, where the length of the needle is the same as the width of each space on the checkerboard. Count up how many times the needles falls on a dividing line between any two squares on the checkerboard. If you calculate the number 2, times the number of times you drop the needle, divided by the number of times the needle falls on a dividing line, the answer is about 3.14.

"There are many other examples, so keep your eyes out for unexpected appearances of the world famous constant pi, especially on March 14!" Musolino said.

For the mathematically challenged, Pi Day can be celebrated with food, including the baking and eating of pies. If you prefer to observe Pi Day in the kitchen rather than the classroom, Chef Katie Horan, pastry chef at NCC's Hampton Winds Restaurant, is here to help and shares helpful baking tips and a pie recipe.


  1. Cold Butter, Cold Dough! Always make sure your butter for your pie dough is cold and cut into small pieces before adding to your dry ingredients. Also, make sure you give your dough at least 30 minutes to chill in the refrigerator-the longer the better! I also like to put the finished rolled out pie dough in the pan back in the fridge before baking, keeping the dough cold will give you a beautiful flaky crust.
  2. Use your hands! You can use a pastry cutter if need be, but I always get the best results by breaking up the butter and working it in with my hands. You can feel the pieces of the butter and it makes it easier to control how big the pieces are. You want the butter to be pea-sized.
  3. Have fun with spices! With a fruit pie, I love playing with the spices until I get a flavor I love. You can taste the filling before baking it to make sure you have enough spice and adjust to taste. If you really want to bring out the flavors, add a little salt! It’s not just for savory cooking, it really elevates your flavors. Just be careful not to add too much!

Butter Pie Crust- makes 2 pies  

2 ½ cups all-purpose flour

1 teaspoon salt

1 tablespoon sugar

2 sticks butter, cold, cut into cubes

1 cup cold water

¼ cup apple cider vinegar

½ cup ice


  1. Stir the flour, salt, and sugar together in a large bowl
  2. Add the butter pieces and cut in using your fingers, working quickly, until pea sized pieces of butter are left
  3. Combine water, ice, and vinegar in a separate container
  4. Add 2T of water mixture at a time and work into the dough until it forms a dough ball with some dry bits remaining
  5. Shape the dough into 2 flat discs, wrap in plastic and refrigerate
  6. You can also freeze this dough up to 1 month


Apple Pie


½ cup sugar

½ cup brown sugar

3 tablespoons all-purpose flour

1 teaspoon cinnamon

¼ teaspoon ginger

¼ teaspoon nutmeg

1/8 teaspoon salt

6-7 cups peeled sliced apples (I like to use granny smith but you can mix it up!)

1 tablespoon lemon juice

1 teaspoon vanilla extract

1 tablespoon butter

1 egg white

Sugar in the raw, as needed

  1. In a small bowl, combine the sugars, flour, and spices; set aside. In a large bowl, toss the apples with the lemon juice to coat the apples. Add the sugar mixture and vanilla extract, combine until all the apples are coated.
  2. Line a pie plate with your bottom crust, fill with apple mixture, cut the butter into small pieces and scatter on top of the apples.
  3. Top the pie with the second crust, you can get creative and do a lattice design, or save time and cover the whole crust, just be sure to cut slits in the top to ventilate the pie. Trim the edges and crimp the crust
  4. Beat the egg white and brush the crust, top with sugar in the raw. Cover the edges loosely with foil so they do not burn
  5. Bake at 375 for 25 minutes. Remove the foil and bake until the crust is golden brown and filling is bubbly, about 20-25 minutes longer. Cool on a wire rack.

Happy Baking!

Happy Pi(e) Day!