Creating a Report Formula - Using a Field drop down option

Hi, I am working to create a report formula for a summary report I am trying to create. I want there to be a new column in the report with numbers I calculate only for the report. My understanding is that I am able to create a field for a single report, but I am having trouble writing the actual formula. 

The form I am working from has a field called "Submission Status" which then has drop down options (Closed and Opened). 

Can you help me write the formula that would allow me to sum the number of submissions from Closed and Opened. 

Sum ([Submission Status], [Submission Status])  --> I know this is not right but I don't know how to get into the Closed and Opened options within the Submission Status field

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Emma Robinson
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