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Highest Common Factor – HCF

What is highest common factor?

The largest common factor of two or more numbers is called the highest common factor (HCF).

Other names for highest common factor

Greatest common divisor or greatest common factor (GCF)

Find the HCF of 12 and 16

Step 1:

First find the factors of numbers given, which means;

List all the factors of 12 and 16

1 , 2 , 4 , 8 , 16

Step 2:

Group the common factors.

What are common factors?

Common factors are the factors that are found in both lists of factors.

1 , 2 , 4 , 8 , 16

So, the common factors of 12 and 16 are 1 , 2 and 4.

Step 3:

Now choose the highest factor of the common factors.

Find the HCF of 15 , 30 and 60

Step 1:

List all the factors of 15 , 30 and 60

1 , 2 , 3 , 4 , 5 , 6 , 10 , 12 , 15 , 20 , 30 , 60

Step 2:

Group the common factors.

1 , 2 , 3 , 4 , 5 , 6 , 10 , 12 , 15 , 20 , 30 , 60

So, common factors of 15 , 30 and 60 are 1 , 3 , 5 and 15.

Step 3:

Now choose the highest of the common factors.

It is 15.

Therefore the HCF of 15 , 30 and 60 is 15.

Hope you have learned the way to find the highest common factor (HCF) or the greatest common factor (greatest common divisor). Try the HCF Quiz.