# Power BI | Creating measures in DAX exercise | Use two variables and the CALCULATE function to create a ratio

This exercise is provided to allow potential course delegates to choose the correct Wise Owl Microsoft training course, and may not be reproduced in whole or in part in any format without the prior written consent of Wise Owl.

You can learn how to do this exercise on the relevant Wise Owl classroom training course (sadly for the moment only in the UK).

 Software ==> Power BI  (92 exercises) Version ==> Latest update Topic ==> Creating measures in DAX  (1 exercise) Level ==> Average difficulty
Before you can do this exercise, you'll need to download and unzip this file (if you have any problems doing this, click here for help).

You need a minimum screen resolution of about 700 pixels width to see our exercises. This is because they contain diagrams and tables which would not be viewable easily on a mobile phone or small laptop. Please use a larger tablet, notebook or desktop computer, or change your screen resolution settings.

Create a new Power BI Desktop file, and load the tables from the workbook in the above folder into your model.  Using variables, create a measure which allows you to show this matrix:

The matrix shows for each cell the ratio between sales for that cell and sales for four- and six-legged animals for the same filter context.

Here's a suggestion of variables to create within your measure:

Variable What it could equal
FourLeggedSales The total quantity of sales for the current filter context, but for animals with 4 legs
SixLeggedSales The total quantity of sales for the current filter context, but for animals with 6 legs
ManyLeggedRatio A/B, where A = the total quantity of sales for the current filter context, and B = the sum of the previous two variables

Save this workbook as Variable fun, then close down the Power BI instance you're using.

You can unzip this file to see the answers to this exercise, although please remember this is for your personal use only.