How to Find the LCM of Two Numbers Using Recursion in Python

Submitted by razormist on Wednesday, October 22, 2025 - 22:21.

In this tutorial, we will learn how to program "How to Find the LCM of Two Numbers Using Recursion in Python". The objective is to find the least common multiple (LCM) of two numbers using a recursive method. This tutorial will guide you step by step through the process of computing the LCM with recursion. By the end of this tutorial, you will have a solid understanding of how to implement this task effectively in Python, helping you strengthen your problem-solving skills and improve your coding abilities.

This topic is straightforward and easy to understand. Simply follow the instructions provided, and you will complete it with ease. The program will guide you step by step through the process of finding the LCM. So, let’s dive into the coding process!

Getting Started:

First you will have to download & install the Python IDLE's, here's the link for the Integrated Development And Learning Environment for Python https://www.python.org/downloads/.

Creating Main Function

This is the main function of the application. The following code will display a simple GUI in terminal console that will display program. To do this, simply copy and paste these blocks of code into the IDLE text editor.

def lcm(a, b):
    lcm.multiple += b
    if (lcm.multiple % a == 0) and (lcm.multiple % b == 0):
        return lcm.multiple
    else:
        return lcm(a, b)
 
while True:
    print("\n============== Find the LCM of Two Numbers Using Recursion ==============\n")
    
    # Initialize multiple before every new calculation
    lcm.multiple = 0
    
    a = int(input("Enter first number: "))
    b = int(input("Enter second number: "))
    
    # Call LCM recursively
    if a > b:
        LCM = lcm(b, a)
    else:
        LCM = lcm(a, b)
    
    print(f"The LCM of {a} and {b} is: {LCM}")
    
    opt = input("\nDo you want to try again? (yes/no): ").strip().lower()
    if opt == 'no':
        print("Exiting program...")
        break
    elif opt != 'yes':
        print("Invalid choice. Exiting program...")
        break

This Python program calculates the Least Common Multiple (LCM) of two numbers using recursion. It defines a recursive function `lcm(a, b)` that repeatedly adds the second number until it finds a multiple that is divisible by both input numbers. Before each new calculation, the variable `lcm.multiple` is reset to zero to ensure accuracy. The program then displays the computed LCM and allows the user to perform multiple calculations or exit the program through a simple menu loop.

Output:

There you have it we successfully created How to Find the LCM of Two Numbers Using Recursion in Python. I hope that this simple tutorial help you to what you are looking for. For more updates and tutorials just kindly visit this site. Enjoy Coding!

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