How do irrational numbers differ from rational numbers?

1 Answer
Mar 29, 2016

Rational numbers can be expressed as fractions, irrational numbers cannot...

Explanation:

Rational numbers can be expressed in the form p/q for some integers p and q (with q != 0). Note that this includes integers, since for any integer n = n/1.

For example, 5, 1/2, 17/3 and -7/2 are all rational numbers.

Any other Real number is called irrational. For example sqrt(2), pi, e are all irrational numbers.

If a number x is rational, then its decimal expansion will either terminate or repeat.

For example, 213/7 = 30.428571428571..., which we can write as 30.bar(428157).

If a number is irrational, then its decimal expansion will neither terminate nor repeat. For example,

pi = 3.141592653589793238462643383279502884...