# Power Pivot Principles: The A to Z of DAX Functions – GCD

16 January 2024

*In our long-established Power Pivot Principles articles, we
continue our series on the A to Z of Data Analysis eXpression (DAX) functions. This week, we look at GCD. *

* *

*The ***GCD*** function*

In mathematics, the greatest common divisor (GCD), also known as the greatest common denominator or the highest common factor, of two or more non-zero integers, is the largest positive integer that divides the numbers without a remainder. For example, the GCD of 24 and 18 is 6.

To show this, if we factorise the numbers down to primes:

24 = 2 x 2 x 2 x 3

18 = 2 x 3 x 3

Therefore, the prime numbers shared are:

2 x 3 = 6.

It should be noted that the GCD will also divide the difference between the two (24 – 18 = 6).

A much more efficient method is the Euclidean algorithm, which uses the division algorithm in combination with the observation that the GCD of two numbers also divides their difference:

- Divide 24 by 18 is 1 remainder 6, so
- Divide 18 by 6 is 3 with no remainder.

Therefore, 6 is the GCD of 24 and 18.

The **GCD** function** **is one of the Math and Trig functions which use
to calculate the greatest common divisor of two integers. It has the following syntax:

**GCD****(number1, [number2], …)**

**number1, number2, …**: the**number1**is required and any subsequent numbers are optional. We can enter from one [1] to 255 values and if values we enter is not an integer, it will be truncated.

It should be noted that:

- if any argument is nonnumeric, the
**GCD**function will return*#VALUE!*error - if any argument is less than zero [0] or a
parameter to GCD is >=2^53, the
**GCD**function will return*#NUM!*error - a prime number has only itself and one [1] as even divisors
- this function is not supported for use in DirectQuery mode when used in calculated columns or row-level security (RLS) rules.

Let’s consider the following example, where we have this **TB_Number** Table loaded to the Data Model:

We will write a DAX measure on the calculated column:

**GCD_Example
:= GCD(TB_Number[Value 1],TB_Number[Value 2])**

As we can see here all the greatest common divisor is listed out
here for **Value 1** and **Value 2**.

Come back next week for our next post on Power Pivot in the *Blog** section. In the meantime, please remember we have training in Power Pivot which you can find out more about **here**. If you wish to catch up on past articles in the meantime, you can find all of our Past Power Pivot blogs **here**.*