Examples
Example 1: Find the HCF of 15 and 20.
Solution:
Factors of 15 = 1, 3, 5, 15.
Factors of 20 = 1, 2, 4, 5, 10, 20.
Take the highest common factor.
Here, 5 is the highest common factor of 15 and 20.
Therefore, HCF(15, 20) = 5.
Example 2: Find the HCF of 10 and 15.
Solution:
Factors of 10 = 1, 2, 5, 10.
Factors of 15 = 1, 3, 5, 15.
Take the highest common factor.
Here, 5 is the highest common factor of 10 and 15.
Therefore, HCF(10, 15) = 5.
Example 3: Find the HCF of 8 and 12.
Solution:
Factors of 8 = 1, 2, 4, 8.
Factors of 12 = 1, 2, 3, 4, 6, 12.
Take the highest common factor.
Here, 4 is the highest common factor of 8 and 12.
Therefore, HCF(8, 12) = 4.
Exercise
1. HCF(18,24,36) = 6
2. HCF(20,30) = 10
3. HCF(15,20,25,30) = 5
4. HCF(7,56) = 7
5. HCF(6,12,18) = 6
6. HCF(5,10,15) = 5
7. HCF(7,14,21) = 7
8. HCF(6,9,15,18) = 3
9. HCF(10,15,20) = 5
10. HCF(20,30,40,50) = 10