Arithmetical operation in Grafana - elastic search

I have a dashboard with elastic search data source displaying the total requests(count) and the number of unique request(unique count). I want to perform an arithmetic operation in that column. Divide the total number of request by unique request count and multiply by some number and display in different column in the dashboard as per the requirement.
How to do this.
I am new to grfana . Could you plz help me with this requirement.