Variables based on Date

[blpowerbi11]

Hello,

I'm trying to calculate Inventory Days on Hand (DOH) using DAX. I've created Variables for each month that contains the number of production days in the month. Example: VAR Jan = 19, Feb = 20, etc. I'm just not sure how to write the DAX formula to calculate DOH. In Excel the formula would be Production Days / Inventory Turns. How do I get it to dynamically change for example when I want to review February data. I apologize if my question does not make sense. I'm a newbie to this community. Any assistance is greatly appreciated. 

[ryan_mayu]

@blpowerbi11 

could you pls provide the sample data and expected output?