python

Functions

A function is a small machine: you give it something (the parameters), it does some work, and it gives you back an answer with return.

def triple(n):
    return n * 3

print(triple(5))    # 15
print(triple(10))   # 30

def means "define a function".
The code inside the function is indented (4 spaces). Python uses indentation to know what belongs to the function.
return sends the answer back to whoever called the function.

print vs return: print shows something on the screen for humans. return hands a value back to the program so it can keep using it.

Your mission

Write a function double(n) that returns n times 2.
Write a function greet(name) that returns the string Hello, NAME!. For example greet("Sam") returns "Hello, Sam!".