Summary  
This chapter explains JavaScript’s primitive data types—numbers, strings, and booleans—showing how to identify them with `typeof` and how operations like addition versus string concatenation behave differently.  

General domain of usage  
Data processing in applications

Different kinds of data behave differently in JavaScript, so understanding data types is essential.

A **data type** tells JavaScript how to treat a piece of data.

Note

// Strings
console.log("123" + "123");

// Numbers
console.log(123 + 123);

The interpreter performs **string concatenation** in the first case and **addition** in the second.

## `typeof` Operator
`typeof` returns the type of a value:

let a = 15;
console.log(typeof 23); // number
console.log(typeof a); // number

const b = "today";
console.log(typeof "word"); // string
console.log(typeof b); // string

# Core JavaScript Data Types
## Number

Used for calculations, counters, and math. JavaScript uses a single number type (no separate int/float).

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

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

## String
Used to store and work with text.
Strings must be wrapped in single or double quotes.

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

To identify the string in the code, we should use single or double quotes (e.g., `'some text'` or `"some text"`)

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

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

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

Stick to one style of quotes per project, but switch when needed inside the text.

## Boolean
Represents logical values: `true` or `false`. Used to check conditions and control program flow.

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 value `"number"`?

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

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

Learn the fundamentals of JavaScript, the backbone of dynamic web development. Discover essential concepts like syntax, variables, data types, and operators. Explore how to use conditional statements, loops, and functions to create interactive and efficient programs. Master the building blocks of JavaScript and lay the groundwork for more advanced programming skills.

Discover the fundamentals of JavaScript, including its purpose and syntax. Learn how to work with the console for output and use comments to organize and document your code. These foundational skills will prepare you for a deeper exploration of JavaScript's capabilities.

Explore the building blocks of JavaScript by distinguishing between literals and variables. Understand the core data types, including `null` and arrays, and learn how to manipulate them using array methods.

Learn how to manipulate JavaScript's data types through essential operations. Master assignment, mathematical operations, incrementing and decrementing, comparisons, logical operations, and string concatenation.

Discover how to control the flow of your programs with conditional statements. Master `if`, `else`, and `else if` to instruct JavaScript on making decisions and executing code based on different conditions.

Streamline your code by mastering JavaScript's looping structures. Explore `while`, `do while`, and `for` loops, and learn how to control their behavior using `break` and `continue`. Unlock the power of loops to perform repetitive tasks efficiently.

Discover the power of functions in JavaScript. Learn how to define functions, work with arguments, and use the `return` statement to create reusable and efficient code. Mastering functions will enhance your ability to write clean and modular programs.

Exploring JavaScript Data Types

`typeof` Operator

Core JavaScript Data Types

Number

String

Boolean

1. The `true` and `false` are ___.

2. What is the data type of the value `"number"`?

3. What is the data type of the value `15`?

4. What is the data type of the value `19.32`?

5. What is the data type of the value `true`?

6. Drag values to their types.

Exploring JavaScript Data Types

typeof Operator

Core JavaScript Data Types

Number

String

Boolean

1. The true and false are ___.

2. What is the data type of the value "number"?

3. What is the data type of the value 15?

4. What is the data type of the value 19.32?