March 14 is known around the world as "Pi Day".Pi is something you may remember from math class.It is the number that results when the distance around a circle is divided by the distance across the circle.It is a very important number in geometry as well as for fields like construction and architecture.

    Pi is an irrational number.It never ends.But the way it begins is always this:3.14159.The date March 14,as we write in the United States,is 3-14.American physicist Larry Shaw started Pi Day back in 1988.

    Pi Day is not just for those who enjoy numbers.Many people mark the math-inspired holiday by celebrating"pie",--p-i-e,instead of "Pi'.Pie is a popular dessert in the United States.It is made with a crust on the outside and usually a sweet filling in the middle.Apple pie,pecan pie,and cherry pie are among the best known.Pizza is another kind of pie,It is made with a crust,tomato sauce and other toppings.