# Rational numbersΒΆ

The type of *rational numbers* is written `Q`

, `β`

, or
`Rational`

. The rational numbers can be thought of as the
combination of `π½`

and `β€`

, and include zero, positive and
negative counting numbers, and positive and negative fractions.

```
Disco> :type -3/5
-3 / 5 : β
```

Doing any of the four arithmetic operations (addition, multiplication, subtraction or division) on two rational numbers results in another rational number.

Note that Disco does not have any way to work with *irrational*
numbers such as \(\pi\) or \(\sqrt{2}\); such numbers are
typically not needed in discrete mathematics, and including them would
make the language much more complicated.