Solve this:

Solve this: 6 The LCM of two numbers is 819. Ifthe two numbers are 63 and 117. find the HCF.

252 = 2 x 2 x 7 x 9 

Factorize the HCF 

4 = 2 x 2 

The HCF is the common factor for both numbers whereas the LCM contains all the unique factors of both numbers. 

So, 2 x 2 or 4 is a common factor for both numbers. 
The factors remaining are 7 and 9. 

So, 7 is a factor of one number and 9 is the factor of the second number. 

The first number = 4 x 7 = 28 
The second number = 4 x 9 = 36 

Hope it is clear now. this is an example hope you understand and solve it on your own