Data can be represented in different views. The operations that you do with data can be different for different data types.

> Note
>
> The **Data Type** is a type of information that tell to interpreter how to work with this data.

Let's look at the difference in interpreter behavior:


// First case
console.log("123" + "123");

// Second case
console.log(123 + 123);

In the example, you can see that interpreter performs various operations for each data type.

# typeof()
The `typeof()` operator determines the data type. This operator returns a type of literal, variable, const, function, etc.

let a = 15;
const B = "const";

console.log(typeof(23));
console.log(typeof(a));

console.log(typeof("word"));
console.log(typeof(B));

console.log(typeof(console.log));

# Number
The **number** is a data type used for calculation, counters, math operations, etc.

Unlike other programming languages, JavaScript uses the **number** type instead of the **int** and **float** types.

console.log(typeof(15.25));
console.log(typeof(211));

console.log(typeof(22 + 251));
console.log(typeof(26 / 342));

# String
The **string** is a text data type. You should use the string data type if you need to work with text (change text, print text in the console, give a text to another program, etc.).

let str = "Hello! I'm String and I should help you to work with text!";
console.log(str);

For every text information that you use in your code, you should write quotes (`'some text'` or `"some text"`). The interpreter knows that it is the text information, not a tool or another object.

console.log("text");
console.log('text');

console.log("console.log('text')");
console.log('console.log("text")');

console.log(typeof("10"));

> Note
>
> - Only one quote style (`"text"` or `'text'`) should be used in your code (or project).
> 
> - You can change the quote style when using `'` or `"` in the text:  
> `"She hasn't hat"` or `'He says "Hi!"'`

# Boolean
The **boolean** is a logical data type. Boolean has 2 values: `true` and `false`. Boolean is used to check conditionals that will be described later. 

Boolean allows you to regulate the behavior of code execution and distribute it to different paths. Also, a boolean can use to turn on/off different tools and parameters.

To create a boolean value you should use the `true` or `false` literals (it's not keywords):

console.log(true);
console.log(false);

console.log(typeof(true));
console.log(typeof(false));

console.log(25 > 15);
console.log(15 > 25);

What is the data type of the literal `"number"`?

What is the data type of the literal `15`?

What is the data type of the literal `19.32`?

What is the data type of the literal `true`?

First, let's get acquainted with JavaScript and look at its syntax. In this section, you will get a basic familiarity with the JavaScript syntax to make it easier to learn in detail later on.

Now it's time to learn about the data types that JavaScript works with. We'll start by looking at the difference between literals and variables, and then delve into the various data types.

We have become familiar with the various data types. Now, let's learn how to work with them by learning the operations we can perform with each data type.

Next, we will learn how to control the flow of execution. It's a straightforward process: we can tell the interpreter exactly what to do under certain conditions.

Next, we will explore how to shorten code using repetitive looped actions. We will examine the types of loops available in JavaScript and learn how to work with them.

Finally, to be able to write simple programs, we need to learn about functions that can make our lives much easier. We will learn how to create and use our functions.

typeof()

Number

String

Boolean

The `true` and `false` are ___.

What is the data type of the literal `"number"`?

What is the data type of the literal `15`?

What is the data type of the literal `19.32`?

What is the data type of the literal `true`?

Drag literals to their types.