GCD :- greatest common divisor :- It means the largest number that divide the given two numbers .
Steps :- 1 Find the divisor of given numbers
like we have 27 and 45
factors of 27 :- 1 , 3 , 9 , 27
factors of 45 :- 1 , 3 , 5 , 9 , 15 , 45
there are two common factors { 3 and 9 }
but the greater one is 9
so GCD of 27 and 45 is 9
