**Problem**: Write a Python program to find the LCM of two numbers.

**LCM or Least Common Multiple** of any two positive integers is the minimum number that is divisible by both the given numbers. Example LCM of 5 and 6 is 30.

There are multiple methods to find lcm in python. Let’s see an example of each of them.

## Method 1: Using While Loop

```
print("Enter two numbers")
a = int(input())
b = int(input())
greater = a if a > b else b
while(1):
if(greater%a == 0) and (greater%b == 0):
break
greater += 1
print("LCM: ",greater)
```

**Output**:

`Enter two numbers
8
9
LCM: 72`

This method is not so efficient because we are looping from the greater number to the number which is divisible by both the a and b.

We can efficiently solve lcm in python using gcd as shown below.

## Method 2: LCM using GCD

For any given two numbers the following relationship holds true:

a * b = LCM * GCD

So we can get LCM using `(a*b)/GCD`

.

Let’s do the same but before that I recommend you check how to calculate the GCD of two numbers in Python.

```
def findGCD(l, s):
while(s):
l, s = s, l%s
return l
print("Enter two numbers")
a = int(input())
b = int(input())
GCD = findGCD(a, b)
LCM = (a*b)/GCD
print("LCM: ",LCM)
```

**Output**:

`Enter two numbers
12
4
LCM: 12.0`

In the above method, we are first calculating the GCD of two numbers using Euclidean Algorithm, then we use it in the formula `LCM = (a*b)/GCD`

to compute the LCM of the a and b.