Find Least Common Multiple of 4 and 9 using ladder method..

LCM( 4, 9 ) = 36

Step 1 : Place the numbers inside division bar:

Step 2 : Find a prime number which divides both numbers.

Since there are no primes that divides at least two of given numbers, we conclude that the LCM is a product of starting numbers.

LCM = 4 · 9 = 36

This solution can be visualized using a Venn diagram.

The LCM is equal to the product of all the numbers on the diagram.