# GCD2 Common Divisors and Greatest Common Divisor

In the GCD1, we learned the meaning of **common divisors**. We continue studying the concept in this video and add a new learning namely identifying the greatest among the the common divisors of two or more numbers. The greatest among the common divisors of two or more number is called the **Greatest Common Divisor** (GCD). It is also called the **Greatest Common Factor** (GCF) since factor is synonymous in meaning with factor in this context.

Watch the video above, and then answer the practice exercise below.

**Practice **

Find the common divisors of the following and identify their greatest common divisor (GCD).

1.) 12 and 14

2.) 18 and 26

3.) 15 and 30

4.) 18 and 42

5.) 8 and 17

6.) 12, 18, and 36

The answers to the exercises above are available below this text. Answer the exercises above before scrolling. You may also want to proceed to the **next lesson** which discusses exercises on getting the GCD of two or more numbers.

*Answers to Practice *

*1.) 12 and 14*

* common divisors: 1, 2*

* GCD: 2*

*2.) 18 and 26: 1, 2*

* common divisors: 1, 2*

* GCD: 2*

*3.) 15 and 30*

* common divisors: 1, 3, 5, 15*

* GCD: 15*

*4.) common divisors of 18 and 42: 1, 2, 3, 6*

* common divisors: 1, 2, 3, 6*

* GCD: 6*

*5.) 8 and 17*

* common divisor: 1*

* GCD: 1*

*6.) 12, 18, and 36*

*common divisors: 1, 2, 3, 6*

* GCD: 6*

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