Examples
Example 1: Find the HCF of 15 and 20.
Solution:
Divide the given numbers with least common prime number.
Keep dividing until common factor is present.
So, list of divisors = 5
Here, we multiply all these divisors to calculate the HCF.
Therefore, HCF(15, 20) = 5.
Example 2: Find the HCF of 15 and 25.
Solution:
Divide the given numbers with least common prime number.
Keep dividing until common factor is present.
So, list of divisors = 5
Here, we multiply all these divisors to calculate the HCF.
Therefore, HCF(15, 25) = 5.
Example 3: Find the HCF of 21 and 28.
Solution:
Divide the given numbers with least common prime number.
Keep dividing until common factor is present.
So, list of divisors = 7
Here, we multiply all these divisors to calculate the HCF.
Therefore, HCF(21, 28) = 7.
Exercise
1. HCF(8,12) = 4
2. HCF(18,27,36) = 9
3. HCF(15,20,25,30) = 5
4. HCF(15,25,35) = 5
5. HCF(10,20,30) = 10
6. HCF(14,21,28) = 7
7. HCF(9,12,15) = 3
8. HCF(16,24,32 ) = 8
9. HCF(15,18,24,30) = 3
10. HCF(20,30,40,50) = 10