Common Examples of Irrational Numbers Pi, which begins with 3.14, is one of the most common irrational numbers. ... e, also known as Euler's number, is another common irrational number. ... The Square Root of 2, written as √2, is also an irrational number.
Irrational numbers are numbers that cannot be expressed in the form p/q where p and q are integers and q does not equal 0. They also have non-terminating and non-repeating decimal expansions.