Python Programming for Complete Beginners: A Structured Course

Lesson 5: Functions & Modules

Objective: Write reusable code blocks.

  • Defining functions (def greet():).

  • Return values (return x + y).

  • Built-in modules (import math).

Code Example:

def add(a, b):
    return a + b  

result = add(3, 5)  
print(result)  # Output: 8  

Exercise:

  • Write a function that calculates the average of three numbers.