Find Least Common Multiple of 35 and 21 using ladder method..

LCM( 35, 21 ) = 105

Step 1 : Place the numbers inside division bar:

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

In this example we can divide by 7. If any number is not divisible by 7 write it down unchanged.

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

LCM = 7 · 5 · 3 = 105

This solution can be visualized using a Venn diagram.

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