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 18 and 24.
Solution:
Factors of 18 = 1, 2, 3, 6, 9, 18.
Factors of 24 = 1, 2, 3, 4, 6, 8, 12, 24.
Take the highest common factor.
Here, 6 is the highest common factor of 18 and 24.
Therefore, HCF(18, 24) = 6.
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(75,100,125) = 25
2. HCF(20,30) = 10
3. HCF(63,84,105) = 21
4. HCF(9,12,15) = 3
5. HCF(4,6,8) = 2
6. HCF(14,21,28) = 7
7. HCF(36, 48, 96) = 12
8. HCF(16,24,32) = 8
9. HCF(10,15,20) = 5
10. HCF(20,30,40,50) = 10