# Java Program to Find LCM of Two Numbers

LCM (i.e. Least Common Multiple) is the largest of the two stated numbers that can be divided by both the given numbers.

### Example for LCM of Two Numbers

Input: LCM( 15 and 25)
Output: 75

Input: LCM( 3 and 7 )
Output: 21

## Methods to Find LCM

There are certain methods to Find the LCM of two numbers as mentioned below:

• Using if statement
• Using GCD

### 1. Using if statement to Find the LCM of Two Numbers

Using if is a really simple method and also can be said brute force method.

Below is the implementation of the above method:

## Java

 // Java Program to find // the LCM of two numbers import java.io.*;   // Driver Class class GFG {     // main function     public static void main(String[] args)     {         // Numbers         int a = 15, b = 25;           // Checking for the smaller         // Number between them         int ans = (a > b) ? a : b;           // Checking for a smallest number that         // can de divided by both numbers         while (true) {             if (ans % a == 0 && ans % b == 0)                 break;             ans++;         }           // Printing the Result         System.out.println("LCM of " + a + " and " + b                            + " : " + ans);     } }

Output

LCM of 15 and 25 : 75

### 2. Using Greatest Common Divisor

Below given formula for finding the LCM of two numbers â€˜uâ€™ and â€˜vâ€™ gives an efficient solution.

u x v = LCM(u, v) * GCD (u, v)
LCM(u, v) = (u x v) / GCD(u, v)

Here, GCD is the greatest common divisor.

## Java

 // Java program to find LCM // of two numbers. class gfg {     // Gcd of u and v     // using recursive method     static int GCD(int u, int v)     {         if (u == 0)             return v;         return GCD(v % u, u);     }       // LCM of two numbers     static int LCM(int u, int v)     {         return (u / GCD(u, v)) * v;     }       // main method     public static void main(String[] args)     {         int u = 25, v = 15;         System.out.println("LCM of " + u + " and " + v                            + " is " + LCM(u, v));     } }

Output

LCM of 25 and 15 is 75

#### Complexity of the above method:

Time Complexity: O(log(min(a,b))
Auxiliary Space: O(log(min(a,b))

Whether you're preparing for your first job interview or aiming to upskill in this ever-evolving tech landscape, GeeksforGeeks Courses are your key to success. We provide top-quality content at affordable prices, all geared towards accelerating your growth in a time-bound manner. Join the millions we've already empowered, and we're here to do the same for you. Don't miss out - check it out now!

Previous
Next