**What is GCD?**

The GCD of two or more integers refers to a positive number that can divide all the numbers without a remainder.

**GCD synonyms**

**HCF** – Highest Common factor

**GCF**– Greatest Common Factor

**HCD** – Highest Common divisor

**How to Find GCD**

You can find the GCD using 3 methods which are factoring, LCM and Long Division. Let’s look at each method.

**Factoring method**

You can simply find the GCD of numbers by listing their factors and then determining the largest number that divides all of them. This is an exhaustive process especially with numbers with many factors. You can find the factors using the factors calculator then compare them.

**Example:** Find the GCD of **6, 8** and **12**

**Step 1:** List the factors of all the three integers

Factors of **6:** **1, 2, 3** and **6**

Factors of **8:** **1, 2, 4** and **8**

Factors of **12: 1, 2, 3, 4** and **12**

**Step 2:** Identify the greatest number which can divide all the numbers

In this case,** 2** is the largest factor that can divide all the three numbers

Therefore **2** is the GCD

**Using the LCM method**

Step 1: Multiply a by b

Step 2: Find the LCM of a and b

Step 3: Divide the answer in step 1 by the answer in step 2

**Example 1:** Find the GCD of 12 and 36 using The LCM method

12 multiplied 36 is 432

The LCM of 12 and 36 is 36

So GCD (12, 36) = 432 ¸ 36

Therefore GCD (12, 36) is **12 **

**Example 2:** Find the GCD of 18 and 24 using the LCM method

The product of 18 and 24 is 432

The LCM of 18 and 24 is 72

So GCD (18, 24) = 432 ¸ 72

Therefore GCD (18, 24) = **6**

**Using Long Division**

You can find the GCD of two numbers without factoring them using Long Division

In Euclidean algorithm you can calculate the GCD of two numbers (a, b) by following these steps

**If a = 0** then we can represent the GCD as **(0, b) = b**

**If b = 0** then we can represent the GCD as **(0, a) = a**

If both are not equal to 0 then we will represent “a” in the quotient remainder form such that **(a = b ****× q + r). q **Stands for Quotient and R stands for remainder.

**Example:** Find the GCD of 14 and 35 using Euclidean algorithm

Divide the large number by the smaller number

Since the remainder is not less than zero, divide the divisor in step one by the remainder in step 2 (14)

Repeat the process until the remainder is zero

Therefore the GCD of 14 and 35 is the corresponding divisor which is **7**

**GCD video tutorial**

**Solved GCD Examples**

**GCD frequently Asked Questions**

**1. How do you Calculate GCD?**

You can calculate the GCD of two or more numbers, by factoring, LCM and Long division methods.

**2. Is GCD and HCF equal?**

GCD and HCF are equal. GCD stands for greatest Common Divisor while HCF stands for Highest Common factor.

**3. What is the GCD of 2 and 2?**

The GCD of 2 and 2 because there is no other number greater than 2 that can divide 2 and 2

**4. What is the fastest way to find GCD?**

The fastest way to find the GCD IS by the LCM method

**5. How do you find the GCD of 3 numbers?**

You can find the GCD of 3 numbers by Prime factorization method For example, let’s find the GCD of 12, 15, and 30

**12 = 2 ****× 2 ****× 3**

**15 = 3 × 5**

**30 = 2 × 3 × 5 **

**3** is the highest common divisor for 12, 15 and 30