Profit is the next measure you will create. You may attempt to write something such as the following:

Profit = SUM('Internet Sales'[Sales Amount]) - SUM('Internet Sales'[Total Product Cost])

This calculation would be technically correct; however, it's not the most efficient way to write code. In fact, another benefit of building explicit measures is that they can be built on top of each other. Reusing existing calculated measures will make the code more readable, and make code changes easier and less time consuming. Imagine for a moment that you discovered that the Total Sales calculation is not correct. If you encapsulated all this logic in a single measure and reused that measure in your other measures, then you need only change the original measure, and any updates would be pushed to all other measures.

Now it's time to create the Profit measure. select your Internet Sales table and then click on New Measure... from the modeling ribbon. Type the following into the formula bar—remember to format it:

Profit = [Total Sales] - [Total Cost]

This calculation returns the same results as the original attempt. The difference is that now you are reusing measures that were already created in the data model. You may have noticed that I referenced the name of the measure without the table name. When referencing explicit measures in your code, it is considered a best practice to exclude the table name.