Functions are reusable blocks of code that perform a specific task. They help organize code and make it more modular.

• Defining: Use the def keyword. def greet(name): print(f"Hello, {name}!")
• Calling: Use the function name followed by parentheses with arguments. greet("Bob") # Output: Hello, Bob!
• Parameters: Variables listed inside the parentheses in the function definition (e.g., name in greet(name)).
• Arguments: Values passed to the function when it is called (e.g., "Bob").
• return statement: Used to send a value back from the function. If omitted, the function returns None by default. def add(x, y): return x + y result = add(5, 3) # result is 8
• Scope: Variables defined inside a function (local scope) are not accessible outside it, unless declared global (generally avoided).