How to add the amount of times each product has sold

[JLaws8]

I have my inventory list on one table. I have another table where I enter the date a product has sold and how many units it sold on that date. I would like add the amount of times each product has sold within the last 30 60 & 90 days on my main table. Is there a good way to do this?

[TheTimeSavingCo]

Yeah, here's a base with that set up.

The idea is to create a formula field that calculates the number of days since the sale, and then use conditonal rollups.  You should be able to see all the formulas if you duplicate the base