Lemma says :
To calculate the Highest Common Factor (HCF) of two positive integers a and b we use Euclid’s division algorithm. HCF is the largest number which exactly divides two or more positive integers. By exactly we mean that on dividing both the integers a and b the remainder is zero.
Given : 135 and 225
Here, 225>135.
So, we will divide greater number by smaller number.
Dividing 225 by 135.
The quotient is 1 and remainder is 90.
225=135×1+90
Divide 135 by 90
The quotient is 1 and remainder is 45.
135=90×1+45
Divide 90 by 45.
The quotient is 2 and remainder is 0.
90=2×45+0
Thus, the HCF is 45.