pi approximation day


Do you love Pi, in July? The fraction 22/7 is an approximation of Pi and since it’s the 22nd of July we wanted to explore more about Pi. Go ahead, you can use it as an excuse to eat some of this yummy dessert!

A fraction represents any number of equal parts.  The fraction 22/7 represents the approximation of Pi. It means it is close but not exactly equal to the value of Pi.

What is the significance of PI?

Pi is a mathematical constant that is the ratio of a circle’s circumference to its diameter. It is approximately equal to 3.14159 or 22/7. A Greek letter (π) is used to represent Pi.

Pi is an irrational number and cannot be expressed exactly as a ratio of any two integers. This is why 22/7 is considered an approximation of Pi.

The Mathletics Dictionary helps us understand these math vocabulary terms.

Irrational number: A number which cannot be written in the form of a/b, where a and b are integers. The exact values of irrational numbers cannot be written as they NEVER end.

Examples of Irrational numbers: π, √2, √3, and 

Integer: Any positive or negative whole number, including zero. Integers are also referred to as directed numbers.

Pi Practice:

Use Pi to find the perimeter of a circle with this Mathletics interactive worksheet.

Instead of using 3.14, try using the fraction 22/7 as the approximation of Pi.

Celebrate Pi Approximation Day:

  • Eat pie! – Can you slice the pie into 7 equal pieces to make one whole?
  • Use fractions today! A fraction describes how many parts of a certain size there are, for example, ½ (one-half), 6/8 (six-eighths), 4/3 (four-thirds).
  • Change the improper fraction to a mixed number.


Take a picture of how you celebrated Pi Approximation Day and share with us on Twitter and Facebook!