HCF means highest common factor . It means the greatest number which can divide the given numbers

HCF is also known as
**
Greatest Common Divisor (GCD)
**

####
**
Find HCF of 4 & 6
**

To find HCF , we do prime factorization of 4 & 6 separately

4 =
**
2
**
× 2

6 =
**
2
**
× 3

HCF of 4 & 6 = 2

####
**
Find HCF of 12 & 16
**

To find HCF , we do prime factorization of 12 & 16 separately

12 =
**
2
**
×
**
2
**
× 3

16 =
**
2
**
×
**
2
**
× 2 × 2

HCF of 12 & 16 = 2 × 2 = 4

####
**
Find HCF of 20, 28, 36
**

Doing Prime factorization of 20, 28 & 36 separately

20 =
**
2
**
×
**
2
**
× 5

28 =
**
2
**
×
**
2
**
× 7

36 =
**
2
**
×
**
2
**
× 3 × 3

So, HCF of 20, 28 & 36 = 2 × 2 = 4

####
**
HCF of 13 & 23
**

**
**

**
**

13 = 13

23 = 23

Since there are no common prime factors ,

only 1 will be the common factor

∴ HCF = 1