### Examples

**Example 1:** Find the HCF of 10, 20 and 30.

**Solution:**

Prime factorization of 10: 10 = 2, 5.

Prime factorization of 20: 20 = 2, 2, 5.

Prime factorization of 30: 30 = 2, 3, 5.

Take the smallest power of common prime factors and multiply them together to get the HCF.

Therefore, HCF(10, 20, 30) = 10.
**Example 2:** Find the HCF of 24, 68 and 10.

**Solution:**

Prime factorization of 24: 24 = 2, 2, 2, 3.

Prime factorization of 68: 68 = 2, 2, 17.

Prime factorization of 10: 10 = 2, 5.

Take the smallest power of common prime factors and multiply them together to get the HCF.

Therefore, HCF(24, 68, 10) = 2.
**Example 3:** Find the HCF of 32, 48 and 96.

**Solution:**

Prime factorization of 32: 32 = 2, 2, 2, 2, 2.

Prime factorization of 48: 48 = 2, 2, 2, 2, 3.

Prime factorization of 96: 96 = 2, 2, 2, 2, 2, 3.

Take the smallest power of common prime factors and multiply them together to get the HCF.

Therefore, HCF(32, 48, 96) = 96.

### Exercise

**1.** HCF(54,72,90) = 18

**2.** HCF(45,63,81) = 9

**3.** HCF(15,25,35) = 5

**4.** HCF(16, 24, 32) = 8

**5.** HCF(10, 15, 20) = 5

**6.** HCF(24, 36, 48) = 12

**7.** HCF(18, 27, 45) = 9

**8.** HCF(24, 40, 56) = 8

**9.** HCF(15, 21, 27) = 3

**10.** HCF(36, 54, 72) = 19