Am I missing something? "... 300-500 ad impressions per day ..." but that's the new app sales per day not the total number of users. If only there was some way

Am I missing something? "... 300-500 ad impressions per day ..." but that's the new app sales per day not the total number of users. If only there was some way to find the area under the sales curve then we could find the total number of users.