Examples
Example 1: Find the HCF of 20 and 60.
Solution:
Factors of 20 = 1, 2, 4, 5, 10, 20.
Factors of 60 = 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60.
Take the highest common factor.
Here, 20 is the highest common factor of 20 and 60.
Therefore, HCF(20, 60) = 20.
Example 2: Find the HCF of 15 and 45.
Solution:
Factors of 15 = 1, 3, 5, 15.
Factors of 45 = 1, 3, 5, 9, 15, 45.
Take the highest common factor.
Here, 15 is the highest common factor of 15 and 45.
Therefore, HCF(15, 45) = 15.
Example 3: Find the HCF of 12 and 8.
Solution:
Factors of 12 = 1, 2, 3, 4, 6, 12.
Factors of 8 = 1, 2, 4, 8.
Take the highest common factor.
Here, 4 is the highest common factor of 12 and 8.
Therefore, HCF(12, 8) = 4.
Exercise
1. HCF(24,36) = 12
2. HCF(18,27) = 9
3. HCF(48,64) = 16
4. HCF(45,50) = 5
5. HCF(12,28) = 4
6. HCF(120,150) = 30
7. HCF(18,30) = 6
8. HCF(30,40) = 10
9. HCF(56,42) = 14
10. HCF(27,63) = 9