Lesson: Basic Arithmetic Operations in Python

 Lesson Objectives

By the end of this lesson, students will be able to:

1. Understand what arithmetic operators are in Python.

2. Use Python to perform addition, subtraction, multiplication, division, modulus, and exponentiation.

3. Take input from the user and display calculated results.

4. Practice basic problem-solving with numbers in Python.

 1. Introduction to Arithmetic Operators

Arithmetic operators are symbols used to perform mathematical operations in Python.
Think of them as the same symbols you use in mathematics but now used in coding.

2. Input and Output in Python

• print(): Displays output on the screen.

• input(): Waits for the user to type something and returns it as a string.

Example:

name = input("Enter your name: ")
print("Hello", name)

Output:

Enter your name: Python Programming
Hello Python Programming

 3. Example Code for Arithmetic

# Declare variables
x = 10
y = 5

# Perform arithmetic operations
sum_result = x + y
diff_result = x - y
product_result = x * y
division_result = x / y

# Display the results
print("Sum:", sum_result)
print("Difference:", diff_result)
print("Product:", product_result)
print("Division:", division_result)

Expected Output:

Sum: 15
Difference: 5
Product: 50
Division: 2.0

4. Interactive Example with User Input

# Take input from the user
x = int(input("Enter the first number: "))
y = int(input("Enter the second number: "))

# Perform arithmetic
print("Sum:", x + y)
print("Difference:", x - y)
print("Product:", x * y)
print("Division:", x / y)
print("Remainder:", x % y)
print("Power:", x ** y)

 5. Practice Tasks for Students

1. Write a program to take two numbers from the user and display:

   • Addition

   • Subtraction

   • Multiplication

   • Division

   • Modulus

2. Ask the user for two numbers and calculate (first number + second number) / 2.

3. Create a program that calculates the area of a rectangle (Area = length × width).

 6. Common Mistakes & How to Avoid Them

• Mistake: Forgetting to convert input to integers.
  ✅ Fix: Use int() or float() when reading numbers.

• Mistake: Dividing by zero.
  ✅ Fix: Always check if the second number is not zero before dividing.