# Rational numbers

A rational number is a number that can be written in the form of a common fraction of two integers. In other words, it is a number that can be represented as one integer divided by another integer. The following are some examples.

### Some things to know about rational numbers

- Rational numbers can be written in the form of a terminating decimal (the decimal ends) or a repeating decimal (the decimal does not end but has repeating digits).
- Non-terminating decimals are not rational numbers because they cannot be expressed in the form of a common fraction.
- The denominator of the common fraction used to express a rational number cannot be 0.
- All integers are rational numbers since the denominator of the common fraction can be 1.

Examples

1. The examples used above can all be converted into either terminating decimals or repeating decimals:

2. The square root of 2 is not a rational number because its decimal never ends so we have no way to express it in the form of a common fraction: