Summary  
This chapter covers using logical operators AND (`&&`), OR (`||`), and NOT (`!`) to combine and evaluate multiple boolean conditions in code.

General domain of usage  
User authentication

You can use logical operators **AND** (`&&`), **OR** (`||`) and **NOT** (`!`) to evaluate multiple conditions simultaneously.

- **AND (`&&`)** returns `true` only if both conditions are true. For example, checking if an account balance is sufficient **and** the withdrawal amount is positive;
  
- **OR (`||`)** returns `true` if at least one condition is true. For example, checking if a balance is sufficient **or** the user has a credit card;

- **NOT (`!`)** negates a condition, turning `true` into `false` and vice versa. For example, checking if an account is **not** locked.

Imagine you need to create conditions for user authentication.

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Which logical operator is used to check if both conditions are true?

Which logical operator is used to check if at least one condition is true?

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Logical Operators

1. Which logical operator is used to check if both conditions are true?

2. Which logical operator is used to check if at least one condition is true?

3. What does the `!` operator do?

Logical Operators

1. Which logical operator is used to check if both conditions are true?

2. Which logical operator is used to check if at least one condition is true?

3. What does the ! operator do?

3. What does the `!` operator do?