Examples
Example 1: Find the HCF of 6, 20 and 72.
Solution:
Factors of 6 = 1, 2, 3, 6.
Factors of 20 = 1, 2, 4, 5, 10, 20.
Factors of 72 = 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72.
Take the highest common factor.
Here, 2 is the highest common factor of 6, 20 and 72.
Therefore, HCF(6, 20, 72) = 2.
Example 2: Find the HCF of 21, 33 and 69.
Solution:
Factors of 21 = 1, 3, 7, 21.
Factors of 33 = 1, 3, 11, 33.
Factors of 69 = 1, 3, 23, 69.
Take the highest common factor.
Here, 3 is the highest common factor of 21, 33 and 69.
Therefore, HCF(21, 33, 69) = 3.
Example 3: Find the HCF of 16, 52 and 56.
Solution:
Factors of 16 = 1, 2, 4, 8, 16.
Factors of 52 = 1, 2, 4, 13, 26, 52.
Factors of 56 = 1, 2, 4, 7, 8, 14, 28, 56.
Take the highest common factor.
Here, 4 is the highest common factor of 16, 52 and 56.
Therefore, HCF(16, 52, 56) = 4.
Exercise
1. HCF(9,15,27) = 3
2. HCF(14,21,28) = 7
3. HCF(8,16,24) = 8
4. HCF(8, 48, 72) = 8
5. HCF(12, 16, 56) = 4
6. HCF(22, 33, 55) = 11
7. HCF(23, 52, 130) = 1
8. HCF(12, 18, 24) = 6
9. HCF(45, 50, 55 ) = 5
10. HCF(32, 48, 54) = 2