If it's not what You are looking for type in the calculator fields your own values, and You will get the solution.
To get the Greates Common Factor (GCF) of 1815 and 195 we need to factor each value first and then we choose all the copies of factors and multiply them:
|1815: ||3||5||11||11|| |
|195: ||3||5|| || ||13|
|GCF: ||3||5|| || || |
The Greates Common Factor (GCF) is: 3 x 5 = 15