Course of Raku / Essentials / Numbers

# Floating-point numbers

In the previous section, we saw that numbers such as `1.5`

are rational numbers. To make a number that corresponds to a `double`

number in C++, use scientific notation:

```
1E0
314e-2
-5e-20
5.424E40
7.6e+15
```

In this case, Raku creates instances of the `Num`

data type and stores the data as an IEEE number internally.

## Built-in constants

There are a few constants listed below that you can use straight ahead. They are the numbers of the `Num`

type. Both ASCII and Unicode variants are available:

`pi` |
`π` |
3.141592653589793 |

`tau` |
`τ` |
equals to `2 * π` |

`e` |
`𝑒` |
2.718281828459045 |

## Course navigation

← Numbers / Rational numbers | Numbers / Operations with numbers →

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