Inventory and items quantity


I am doing a base dedicated to the inventory of stuff that I use for doing courses. If, for instance, I send to another location a video projector I want the number of available projectors to decrease. And when the video projector returns the quantity should increase. But I don’t know how I could achieve that.
I would appreciate your help.


Solved! I found this: Auto adjust Quantity based on Multiple select field option


Some of the items of my inventory can be send to a course location. How could I specify the number of items that are sent to a location and keep the accounting of the remaining ones?.