# Data Types

There are four basic types of data in BackTalk: numbers, text, booleans, and references.

## 1. Numbers

A number in BackTalk is pretty much what you would expect. For instance, `5` is the number five. You can also do math in BackTalk, and it looks much like you're used to. Try out some math in the example below. Multiplication looks like `2 * 3` and division looks like `9 / 3`.

``````-- SimpleExample

(2 * 2) + (4 + 8) / 3
``````

## 2. Booleans

There are two booleans: `true`, and `false`. Like numbers, there is a kind of math that you can do with booleans.

• You can use `!` to negate them. `! true` is the same as `false`. Notice the space after the `!` this is required in BackTalk.
• You can also use `&` (which is called "and") to check if the first and second booleans are both true. `true & true` is `true`, `true & false` is not.
• You can also use `|` (which is called "or") to check if either the first or the second boolean is true. `true | true` is `true`, but `false | false` is not.
• Finally, you can combine `!`, `&`, and `|` together to make something as complicated as you want! Try it out in the example below.
``````-- SimpleExample

true &! false | true
``````

## 3. Text

Text is a bunch of letters and numbers and things like that. In BackTalk, text looks like `"this"`. Notice that it begins and ends with quotation marks. Try editing the text in the example below.

``````-- SimpleExample

"wow!!!"
``````

## 4. References

What is a references? A reference is like a name. A name tells you which thing I'm talking about, but it isn't the thing itself. If I say, "Suzy is an excellent computer programmer," then you know who I'm talking about, because I used Suzy's name. References in BackTalk work the same way. A reference looks like this:

``````\$suzy
``````

or this

``````\$my_best_friend
``````

or any other bunch of letters and underscores, as long as it starts with a `\$`.

In the following example, you can use a reference to pick a friend to describe. Try switching `\$suzy` for `\$harry` or `\$bingo` in the example below:

``````-- SimpleExample

\$suzy
``````