how are functions useful in python code example

Example 1: python functions

def myFunction(say): #you can add variables to the function
  print(say)

myFunction("Hello")

age = input("How old are you?")

myFunction("You are {} years old!".format(age))

#this is what you get:

Hello
How old are you?
>>11 #lol my real age actually
You are 11 years old!

Example 2: python functions

# first we have to write 'def'
# then our function name followed by ()
# and a ':' abd defining  block of code

def multiply():     # naming convention could be same as variable for functions
    product = 10.5 * 4
    return product


product = multiply()
print(product)

Example 3: functions python examples

def multiply(a, b):
  return a * b

print(multiply(4, 4))