Reverse a ratio

[qliker3]

so i have this formula a-b/a+b and i get 2 %. I want to get 98 %. How do i do this? 

[Chanty4u]

May be this 

Sum(Sales) / Sum(Total Sales)

[MarcoWedel · Accepted solution]

I guess you mean (a-b)/(a+b) ?

Then your expected result would be

1-(a-b)/(a+b)

or

(2*b)/(a+b)

Do you have some sample data/results to verify?