In this tutorial, We are going to learn a writing program to calculate the LCM of two numbers.

Before writing a program let’s understand

## What is LCM? How to calculate LCM?

LCM stands for Least Common Divisor, which is a value of two numbers that are evenly divisible by the two given numbers.

**For example:**

LCM of 12 and 15 is 60. Because 60 is the least number which is divided by both 12 and 15.

**LCM Calculation**

To calculate the LCM of numbers first find the factors of the numbers.

Here we are calculating **LCM of 12 and 15**.

Factors of 12 are 2 * 2 * 3

Fact**ors of 15** are 5 * 3

Now take the common number which is in both factors and all the numbers which are not common and multiply them.

Here 3 is common and 2,2 and 5 are not common. So we are taking both and multiplying.

After multiplication 3 * 2* 2* 5 = 60.

**So 60 is the LCM of 12 and 15**.

Let’s see the program

**C program to calculate LCM of given two numbers**

```
#include <stdio.h>
int main() {
int num1, num2, maxNum;
printf("Program to find LCM of two numbers\n");
printf("Enter the first number: ");
scanf("%d", &num1);
printf("Enter the second number: ");
scanf("%d", &num2);
maxNum = (num1 > num2) ? num1 : num2;
while (1) {
if (maxNum % num1 == 0 && maxNum % num2 == 0) {
printf("The LCM of %d and %d is %d", num1, num2, maxNum);
break;
}
++maxNum;
}
return 0;
}
```

**Output**

```
Program to find LCM of two numbers
Enter the first number: 23
Enter the second number: 45
The LCM of 23 and 45 is 1035
```

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