Find Least Common Multiple of 25, 42 and 81 using ladder method..

LCM( 25, 42, 81 ) = 28350

Step 1 : Place the numbers inside division bar:

Step 2 : Find a prime number which can divide at least two of your numbers.

In this example we can divide by 3. If any number is not divisible by 3 write it down unchanged.

Step 4 : LCM is a product of numbers into L shape.

LCM = 3 · 25 · 14 · 27 = 28350

This solution can be visualized using a Venn diagram.

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